<P> When more than one senator has served in the same previous role, length of time in that prior office is used to break the tie . For instance, Ben Cardin, Bernie Sanders, Sherrod Brown, Bob Casey, Bob Corker, Claire McCaskill, Amy Klobuchar, Sheldon Whitehouse and Jon Tester took office on January 3, 2007, and the first three senators mentioned had previously served in the House of Representatives . Cardin, having served 20 years, is more senior than Sanders, who served 16 years, who in turn is more senior than Brown who served 14 years . Casey, Corker, McCaskill, Klobuchar, Whitehouse, and Tester rank in that order because as of the 2000 census, Pennsylvania, Tennessee, Missouri, Minnesota, Rhode Island, and Montana had populations that ranked in that order, so Tester was ranked 100th in seniority when the 110th Congress convened . </P> <P> Only relevant factors are listed below . For senators whose seniority is based on their state's respective population, the state population ranking is given as determined by the relevant United States Census current at the time that they first took their seat . </P> <Table> <Tr> <Th_colspan="8"> <P> Republican R (51) Democratic D (47) Independent I (2) </P> </Th> </Tr> <Tr> <Th> Current rank </Th> <Th> Historical rank </Th> <Th_colspan="2"> Senator party - state </Th> <Th> Seniority date </Th> <Th> First tie - breaker </Th> <Th> Second tie - breaker </Th> <Th> Committee and leadership positions </Th> </Tr> <Tr> <Th> </Th> <Th> 1692 </Th> <Td> </Td> <Td> Patrick Leahy D--Vermont </Td> <Td> January 3, 1975 </Td> <Td> </Td> <Td> </Td> <Td> Ranking Member: Appropriations President pro tempore emeritus </Td> </Tr> <Tr> <Th> </Th> <Th> 1708 </Th> <Td> </Td> <Td> Orrin Hatch R--Utah </Td> <Td> January 3, 1977 </Td> <Td> President pro tempore Chair: Finance </Td> </Tr> <Tr> <Th> </Th> <Th> 1745 </Th> <Td> </Td> <Td> Chuck Grassley R--Iowa </Td> <Td> January 3, 1981 </Td> <Td> Chair: Judiciary </Td> </Tr> <Tr> <Th> </Th> <Th> 1766 </Th> <Td> </Td> <Td> Mitch McConnell R--Kentucky </Td> <Td> January 3, 1985 </Td> <Td> Majority Leader </Td> </Tr> <Tr> <Th> 5 </Th> <Th> 1775 </Th> <Td> </Td> <Td> Richard Shelby R--Alabama </Td> <Td> January 3, 1987 </Td> <Td> Chair: Appropriations </Td> </Tr> <Tr> <Th> 6 </Th> <Th> 1801 </Th> <Td> </Td> <Td> Dianne Feinstein D--California </Td> <Td> November 4, 1992 </Td> <Td> Ranking Member: Judiciary </Td> </Tr> <Tr> <Th> 7 </Th> <Th> 1810 </Th> <Td> </Td> <Td> Patty Murray D--Washington </Td> <Td> January 3, 1993 </Td> <Td> Ranking Member: HELP Assistant Minority Leader </Td> </Tr> <Tr> <Th> 8 </Th> <Th> 1816 </Th> <Td> </Td> <Td> Jim Inhofe R--Oklahoma </Td> <Td> November 16, 1994 </Td> <Td> Chair: Armed Services </Td> </Tr> <Tr> <Th> 9 </Th> <Th> 1827 </Th> <Td> </Td> <Td> Ron Wyden D--Oregon </Td> <Td> February 6, 1996 </Td> <Td> Ranking Member: Finance </Td> </Tr> <Tr> <Th> 10 </Th> <Th> 1830 </Th> <Td> </Td> <Td> Pat Roberts R--Kansas </Td> <Td> January 3, 1997 </Td> <Td> Former representative (16 years) </Td> <Td> Chair: Agriculture </Td> </Tr> <Tr> <Th> 11 </Th> <Th> 1831 </Th> <Td> </Td> <Td> Dick Durbin D--Illinois </Td> <Td> Former representative (14 years) </Td> <Td> Minority Whip </Td> </Tr> <Tr> <Th> 12 </Th> <Th> 1835 </Th> <Td> </Td> <Td> Jack Reed D--Rhode Island </Td> <Td> Former representative (6 years) </Td> <Td> Ranking Member: Armed Services </Td> </Tr> <Tr> <Th> 13 </Th> <Th> 1842 </Th> <Td> </Td> <Td> Susan Collins R--Maine </Td> <Td> Maine 38th in population (1990) </Td> <Td> Chair: Aging </Td> </Tr> <Tr> <Th> 14 </Th> <Th> 1843 </Th> <Td> </Td> <Td> Mike Enzi R--Wyoming </Td> <Td> Wyoming 50th in population (1990) </Td> <Td> Chair: Budget </Td> </Tr> <Tr> <Th> 15 </Th> <Th> 1844 </Th> <Td> </Td> <Td> Chuck Schumer D--New York </Td> <Td> January 3, 1999 </Td> <Td> Former representative (18 years) </Td> <Td> Minority Leader </Td> </Tr> <Tr> <Th> 16 </Th> <Th> 1846 </Th> <Td> </Td> <Td> Mike Crapo R--Idaho </Td> <Td> Former representative (6 years) </Td> <Td> Chair: Banking </Td> </Tr> <Tr> <Th> 17 </Th> <Th> 1854 </Th> <Td> </Td> <Td> Bill Nelson D--Florida </Td> <Td> January 3, 2001 </Td> <Td> Former representative (12 years) </Td> <Td> Ranking Member: Commerce </Td> </Tr> <Tr> <Th> 18 </Th> <Th> 1855 </Th> <Td> </Td> <Td> Tom Carper D--Delaware </Td> <Td> Former representative (10 years) </Td> <Td> Ranking Member: Environment </Td> </Tr> <Tr> <Th> 19 </Th> <Th> 1856 </Th> <Td> </Td> <Td> Debbie Stabenow D--Michigan </Td> <Td> Former representative (4 years) </Td> <Td> Ranking Member: Agriculture Democratic Policy Committee Chair </Td> </Tr> <Tr> <Th> 20 </Th> <Th> 1859 </Th> <Td> </Td> <Td> Maria Cantwell D--Washington </Td> <Td> Former representative (2 years) </Td> <Td> Ranking Member: Energy </Td> </Tr> <Tr> <Th> 21 </Th> <Th> 1867 </Th> <Td> </Td> <Td> Lisa Murkowski R--Alaska </Td> <Td> December 20, 2002 </Td> <Td> </Td> <Td> Chair: Energy </Td> </Tr> <Tr> <Th> 22 </Th> <Th> 1869 </Th> <Td> </Td> <Td> Lindsey Graham R--South Carolina </Td> <Td> January 3, 2003 </Td> <Td> Former representative </Td> <Td> </Td> </Tr> <Tr> <Th> 23 </Th> <Th> 1871 </Th> <Td> </Td> <Td> Lamar Alexander R--Tennessee </Td> <Td> Former Cabinet member </Td> <Td> Chair: HELP </Td> </Tr> <Tr> <Th> 24 </Th> <Th> 1873 </Th> <Td> </Td> <Td> John Cornyn R--Texas </Td> <Td> </Td> <Td> Majority Whip </Td> </Tr> <Tr> <Th> 25 </Th> <Th> 1876 </Th> <Td> </Td> <Td> Richard Burr R--North Carolina </Td> <Td> January 3, 2005 </Td> <Td> Former representative (10 years) </Td> <Td> Chair: Intelligence </Td> </Tr> <Tr> <Th> 26 </Th> <Th> 1879 </Th> <Td> </Td> <Td> John Thune R--South Dakota </Td> <Td> Former representative (6 years) </Td> <Td> Chair: Commerce Republican Conference Chair </Td> </Tr> <Tr> <Th> 27 </Th> <Th> 1880 </Th> <Td> </Td> <Td> Johnny Isakson R--Georgia </Td> <Td> Former representative (5 yrs., 10 mos .) </Td> <Td> Chair: Veterans' Affairs Chair: Ethics </Td> </Tr> <Tr> <Th> 28 </Th> <Th> 1885 </Th> <Td> </Td> <Td> Bob Menendez D--New Jersey </Td> <Td> January 17, 2006 </Td> <Td> </Td> <Td> Ranking Member: Foreign Relations </Td> </Tr> <Tr> <Th> 29 </Th> <Th> 1886 </Th> <Td> </Td> <Td> Ben Cardin D--Maryland </Td> <Td> January 3, 2007 </Td> <Td> Former representative (20 years) </Td> <Td> Ranking Member: Small Business </Td> </Tr> <Tr> <Th> 30 </Th> <Th> 1887 </Th> <Td> </Td> <Td> Bernie Sanders I--Vermont </Td> <Td> Former representative (16 years) </Td> <Td> Ranking Member: Budget </Td> </Tr> <Tr> <Th> 31 </Th> <Th> 1888 </Th> <Td> </Td> <Td> Sherrod Brown D--Ohio </Td> <Td> Former representative (14 years) </Td> <Td> Ranking Member: Banking </Td> </Tr> <Tr> <Th> 32 </Th> <Th> 1890 </Th> <Td> </Td> <Td> Bob Casey Jr . D--Pennsylvania </Td> <Td> Pennsylvania 6th in population (2000) </Td> <Td> Ranking Member: Aging </Td> </Tr> <Tr> <Th> 33 </Th> <Th> 1891 </Th> <Td> </Td> <Td> Bob Corker R--Tennessee </Td> <Td> Tennessee 16th in population (2000) </Td> <Td> Chair: Foreign Relations </Td> </Tr> <Tr> <Th> 34 </Th> <Th> 1892 </Th> <Td> </Td> <Td> Claire McCaskill D--Missouri </Td> <Td> Missouri 17th in population (2000) </Td> <Td> Ranking Member: Homeland Security </Td> </Tr> <Tr> <Th> 35 </Th> <Th> 1893 </Th> <Td> </Td> <Td> Amy Klobuchar D--Minnesota </Td> <Td> Minnesota 21st in population (2000) </Td> <Td> Ranking Member: Rules </Td> </Tr> <Tr> <Th> 36 </Th> <Th> 1894 </Th> <Td> </Td> <Td> Sheldon Whitehouse D--Rhode Island </Td> <Td> Rhode Island 43rd in population (2000) </Td> <Td> </Td> </Tr> <Tr> <Th> 37 </Th> <Th> 1895 </Th> <Td> </Td> <Td> Jon Tester D--Montana </Td> <Td> Montana 44th in population (2000) </Td> <Td> Ranking Member: Veterans' Affairs </Td> </Tr> <Tr> <Th> 38 </Th> <Th> 1896 </Th> <Td> </Td> <Td> John Barrasso R--Wyoming </Td> <Td> June 22, 2007 </Td> <Td> </Td> <Td> Chair: Environment Republican Policy Committee Chair </Td> </Tr> <Tr> <Th> 39 </Th> <Th> 1897 </Th> <Td> </Td> <Td> Roger Wicker R--Mississippi </Td> <Td> December 31, 2007 </Td> <Td> </Td> </Tr> <Tr> <Th> 40 </Th> <Th> 1899 </Th> <Td> </Td> <Td> Tom Udall D--New Mexico </Td> <Td> January 3, 2009 </Td> <Td> Former representative </Td> <Td> Vice Chair: Indian Affairs </Td> </Tr> <Tr> <Th> 41 </Th> <Th> 1901 </Th> <Td> </Td> <Td> Jeanne Shaheen D--New Hampshire </Td> <Td> Former governor (6 years) </Td> <Td> </Td> </Tr> <Tr> <Th> 42 </Th> <Th> 1902 </Th> <Td> </Td> <Td> Mark Warner D--Virginia </Td> <Td> Former governor (4 years) </Td> <Td> Vice Chair: Intelligence Democratic Caucus Vice Chair </Td> </Tr> <Tr> <Th> 43 </Th> <Th> 1903 </Th> <Td> </Td> <Td> Jim Risch R--Idaho </Td> <Td> Former governor (7 months) </Td> <Td> Chair: Small Business </Td> </Tr> <Tr> <Th> 44 </Th> <Th> 1905 </Th> <Td> </Td> <Td> Jeff Merkley D--Oregon </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Th> 45 </Th> <Th> 1909 </Th> <Td> </Td> <Td> Michael Bennet D--Colorado </Td> <Td> January 21, 2009 </Td> </Tr> <Tr> <Th> 46 </Th> <Th> 1910 </Th> <Td> </Td> <Td> Kirsten Gillibrand D--New York </Td> <Td> January 26, 2009 </Td> </Tr> <Tr> <Th> 47 </Th> <Th> 1916 </Th> <Td> </Td> <Td> Joe Manchin D--West Virginia </Td> <Td> November 15, 2010 </Td> <Td> Former governor </Td> </Tr> <Tr> <Th> 48 </Th> <Th> 1917 </Th> <Td> </Td> <Td> Chris Coons D--Delaware </Td> <Td> </Td> <Td> Vice Chair: Ethics </Td> </Tr> <Tr> <Th> 49 </Th> <Th> 1919 </Th> <Td> </Td> <Td> Roy Blunt R--Missouri </Td> <Td> January 3, 2011 </Td> <Td> Former representative (14 years) </Td> <Td> Missouri 17th in population (2000) </Td> <Td> Chair: Rules Republican Conference Vice Chair </Td> </Tr> <Tr> <Th> 50 </Th> <Th> 1920 </Th> <Td> </Td> <Td> Jerry Moran R--Kansas </Td> <Td> Kansas 33rd in population (2000) </Td> <Td> </Td> </Tr> <Tr> <Th> 51 </Th> <Th> 1921 </Th> <Td> </Td> <Td> Rob Portman R--Ohio </Td> <Td> Former representative (12 years) </Td> <Td> </Td> </Tr> <Tr> <Th> 52 </Th> <Th> 1922 </Th> <Td> </Td> <Td> John Boozman R--Arkansas </Td> <Td> Former representative (10 years) </Td> </Tr> <Tr> <Th> 53 </Th> <Th> 1923 </Th> <Td> </Td> <Td> Pat Toomey R--Pennsylvania </Td> <Td> Former representative (6 years) </Td> </Tr> <Tr> <Th> 54 </Th> <Th> 1924 </Th> <Td> </Td> <Td> John Hoeven R--North Dakota </Td> <Td> Former governor </Td> <Td> Chair: Indian Affairs </Td> </Tr> <Tr> <Th> 55 </Th> <Th> 1925 </Th> <Td> </Td> <Td> Marco Rubio R--Florida </Td> <Td> Florida 4th in population (2000) </Td> <Td> </Td> </Tr> <Tr> <Th> 56 </Th> <Th> 1926 </Th> <Td> </Td> <Td> Ron Johnson R--Wisconsin </Td> <Td> Wisconsin 20th in population (2000) </Td> <Td> Chair: Homeland Security </Td> </Tr> <Tr> <Th> 57 </Th> <Th> 1927 </Th> <Td> </Td> <Td> Rand Paul R--Kentucky </Td> <Td> Kentucky 25th in population (2000) </Td> <Td> </Td> </Tr> <Tr> <Th> 58 </Th> <Th> 1928 </Th> <Td> </Td> <Td> Richard Blumenthal D--Connecticut </Td> <Td> Connecticut 29th in population (2000) </Td> </Tr> <Tr> <Th> 59 </Th> <Th> 1929 </Th> <Td> </Td> <Td> Mike Lee R--Utah </Td> <Td> Utah 34th in population (2000) </Td> </Tr> <Tr> <Th> 60 </Th> <Th> 1931 </Th> <Td> </Td> <Td> Dean Heller R--Nevada </Td> <Td> May 9, 2011 </Td> <Td> </Td> </Tr> <Tr> <Th> 61 </Th> <Th> 1932 </Th> <Td> </Td> <Td> Brian Schatz D--Hawaii </Td> <Td> December 26, 2012 </Td> </Tr> <Tr> <Th> 62 </Th> <Th> 1933 </Th> <Td> </Td> <Td> Tim Scott R--South Carolina </Td> <Td> January 2, 2013 </Td> </Tr> <Tr> <Th> 63 </Th> <Th> 1934 </Th> <Td> </Td> <Td> Tammy Baldwin D--Wisconsin </Td> <Td> January 3, 2013 </Td> <Td> Former representative (14 years) </Td> <Td> Democratic Caucus Secretary </Td> </Tr> <Tr> <Th> 64 </Th> <Th> 1935 </Th> <Td> </Td> <Td> Jeff Flake R--Arizona </Td> <Td> Former representative (12 years) </Td> <Td> </Td> </Tr> <Tr> <Th> 65 </Th> <Th> 1936 </Th> <Td> </Td> <Td> Joe Donnelly D--Indiana </Td> <Td> Former representative (6 years) </Td> <Td> Indiana 15th in population (2010) </Td> </Tr> <Tr> <Th> 66 </Th> <Th> 1937 </Th> <Td> </Td> <Td> Chris Murphy D--Connecticut </Td> <Td> Connecticut 29th in population (2010) </Td> </Tr> <Tr> <Th> 67 </Th> <Th> 1938 </Th> <Td> </Td> <Td> Mazie Hirono D--Hawaii </Td> <Td> Hawaii 40th in population (2010) </Td> </Tr> <Tr> <Th> 68 </Th> <Th> 1939 </Th> <Td> </Td> <Td> Martin Heinrich D--New Mexico </Td> <Td> Former representative (4 years) </Td> <Td> </Td> </Tr> <Tr> <Th> 69 </Th> <Th> 1940 </Th> <Td> </Td> <Td> Angus King I--Maine </Td> <Td> Former governor (8 years) </Td> </Tr> <Tr> <Th> 70 </Th> <Th> 1941 </Th> <Td> </Td> <Td> Tim Kaine D--Virginia </Td> <Td> Former governor (4 years) </Td> </Tr> <Tr> <Th> 71 </Th> <Th> 1942 </Th> <Td> </Td> <Td> Ted Cruz R--Texas </Td> <Td> Texas 2nd in population (2010) </Td> </Tr> <Tr> <Th> 72 </Th> <Th> 1943 </Th> <Td> </Td> <Td> Elizabeth Warren D--Massachusetts </Td> <Td> Massachusetts 14th in population (2010) </Td> <Td> Democratic Caucus Vice Chair </Td> </Tr> <Tr> <Th> 73 </Th> <Th> 1944 </Th> <Td> </Td> <Td> Deb Fischer R--Nebraska </Td> <Td> Nebraska 38th in population (2010) </Td> <Td> </Td> </Tr> <Tr> <Th> 74 </Th> <Th> 1945 </Th> <Td> </Td> <Td> Heidi Heitkamp D--North Dakota </Td> <Td> North Dakota 48th in population (2010) </Td> </Tr> <Tr> <Th> 75 </Th> <Th> 1948 </Th> <Td> </Td> <Td> Ed Markey D--Massachusetts </Td> <Td> July 16, 2013 </Td> <Td> </Td> </Tr> <Tr> <Th> 76 </Th> <Th> 1949 </Th> <Td> </Td> <Td> Cory Booker D--New Jersey </Td> <Td> October 31, 2013 </Td> </Tr> <Tr> <Th> 77 </Th> <Th> 1951 </Th> <Td> </Td> <Td> Shelley Moore Capito R--West Virginia </Td> <Td> January 3, 2015 </Td> <Td> Former representative (14 years) </Td> </Tr> <Tr> <Th> 78 </Th> <Th> 1952 </Th> <Td> </Td> <Td> Gary Peters D--Michigan </Td> <Td> Former representative (6 years) </Td> <Td> Michigan 8th in population (2010) </Td> </Tr> <Tr> <Th> 79 </Th> <Th> 1953 </Th> <Td> </Td> <Td> Bill Cassidy R--Louisiana </Td> <Td> Louisiana 25th in population (2010) </Td> </Tr> <Tr> <Th> 80 </Th> <Th> 1954 </Th> <Td> </Td> <Td> Cory Gardner R--Colorado </Td> <Td> Former representative (4 years) </Td> <Td> Colorado 22nd in population (2010) </Td> <Td> NRSC Chair </Td> </Tr> <Tr> <Th> 81 </Th> <Th> 1955 </Th> <Td> </Td> <Td> James Lankford R--Oklahoma </Td> <Td> Oklahoma 28th in population (2010) </Td> <Td> </Td> </Tr> <Tr> <Th> 82 </Th> <Th> 1956 </Th> <Td> </Td> <Td> Tom Cotton R--Arkansas </Td> <Td> Former representative (2 years) </Td> <Td> Arkansas 32nd in population (2010) </Td> </Tr> <Tr> <Th> 83 </Th> <Th> 1957 </Th> <Td> </Td> <Td> Steve Daines R--Montana </Td> <Td> Montana 44th in population (2010) </Td> </Tr> <Tr> <Th> 84 </Th> <Th> 1958 </Th> <Td> </Td> <Td> Mike Rounds R--South Dakota </Td> <Td> Former governor </Td> <Td> </Td> </Tr> <Tr> <Th> 85 </Th> <Th> 1959 </Th> <Td> </Td> <Td> David Perdue R--Georgia </Td> <Td> Georgia 9th in population (2010) </Td> </Tr> <Tr> <Th> 86 </Th> <Th> 1960 </Th> <Td> </Td> <Td> Thom Tillis R--North Carolina </Td> <Td> North Carolina 10th in population (2010) </Td> </Tr> <Tr> <Th> 87 </Th> <Th> 1961 </Th> <Td> </Td> <Td> Joni Ernst R--Iowa </Td> <Td> Iowa 30th in population (2010) </Td> </Tr> <Tr> <Th> 88 </Th> <Th> 1962 </Th> <Td> </Td> <Td> Ben Sasse R--Nebraska </Td> <Td> Nebraska 38th in population (2010) </Td> </Tr> <Tr> <Th> 89 </Th> <Th> 1963 </Th> <Td> </Td> <Td> Dan Sullivan R--Alaska </Td> <Td> Alaska 47th in population (2010) </Td> </Tr> <Tr> <Th> 90 </Th> <Th> 1964 </Th> <Td> </Td> <Td> Chris Van Hollen D--Maryland </Td> <Td> January 3, 2017 </Td> <Td> Former representative (14 years) </Td> <Td> DSCC Chair </Td> </Tr> <Tr> <Th> 91 </Th> <Th> 1965 </Th> <Td> </Td> <Td> Todd Young R--Indiana </Td> <Td> Former representative (6 years) </Td> <Td> </Td> </Tr> <Tr> <Th> 92 </Th> <Th> 1966 </Th> <Td> </Td> <Td> Tammy Duckworth D--Illinois </Td> <Td> Former representative (4 years) </Td> </Tr> <Tr> <Th> 93 </Th> <Th> 1967 </Th> <Td> </Td> <Td> Maggie Hassan D--New Hampshire </Td> <Td> Former governor </Td> </Tr> <Tr> <Th> 94 </Th> <Th> 1968 </Th> <Td> </Td> <Td> Kamala Harris D--California </Td> <Td> California 1st in population (2010) </Td> </Tr> <Tr> <Th> 95 </Th> <Th> 1969 </Th> <Td> </Td> <Td> John Neely Kennedy R--Louisiana </Td> <Td> Louisiana 25th in population (2010) </Td> </Tr> <Tr> <Th> 96 </Th> <Th> 1970 </Th> <Td> </Td> <Td> Catherine Cortez Masto D--Nevada </Td> <Td> Nevada 35th in population (2010) </Td> </Tr> <Tr> <Th> 97 </Th> <Th> 1972 </Th> <Td> </Td> <Td> Tina Smith D--Minnesota </Td> <Td> January 3, 2018 </Td> <Td> Minnesota 21st in population (2010) </Td> </Tr> <Tr> <Th> 98 </Th> <Th> 1973 </Th> <Td> </Td> <Td> Doug Jones D--Alabama </Td> <Td> Alabama 23rd in population (2010) </Td> </Tr> <Tr> <Th> 99 </Th> <Th> </Th> <Td> </Td> <Td> Cindy Hyde - Smith R--Mississippi </Td> <Td> April 2, 2018 </Td> </Tr> <Tr> <Th> 100 </Th> <Th> 1819 </Th> <Td> </Td> <Td> Jon Kyl R--Arizona </Td> <Td> September 4, 2018 </Td> </Tr> <Tr> <Th> Rank </Th> <Th> Historical rank </Th> <Th_colspan="2"> Senator party - state </Th> <Th> Seniority date </Th> <Th> First tie - breaker </Th> <Th> Second tie - breaker </Th> <Th> Committee and leadership positions </Th> </Tr> </Table> <Tr> <Th_colspan="8"> <P> Republican R (51) Democratic D (47) Independent I (2) </P> </Th> </Tr>

Who is the top ranking member in the senate