<Tr> <Td> 27 </Td> <Td> Taft, William H. William H. Taft (1857--1930) </Td> <Td> </Td> <Td> 000000001909 - 03 - 04 - 0000 Mar 4, 1909 </Td> <Td> 000000001913 - 03 - 04 - 0000 Mar 4, 1913 </Td> <Td> 7003146100000000000 ♠ 4 years, 0 days </Td> </Tr> <Tr> <Td> 29 </Td> <Td> Harding, Warren G. Warren G. Harding (1865--1923) </Td> <Td> </Td> <Td> 000000001921 - 03 - 04 - 0000 Mar 4, 1921 </Td> <Td> 000000001923 - 08 - 02 - 0000 Aug 2, 1923 </Td> <Td> 7002881000000000000 ♠ 2 years, 151 days </Td> </Tr> <Tr> <Td> 30 </Td> <Td> Coolidge, Calvin Calvin Coolidge (1872--1933) </Td> <Td> </Td> <Td> 000000001923 - 08 - 02 - 0000 Aug 2, 1923 </Td> <Td> 000000001929 - 03 - 04 - 0000 Mar 4, 1929 </Td> <Td> 7003204100000000000 ♠ 5 years, 214 days </Td> </Tr> <Tr> <Td> 31 </Td> <Td> Hoover, Herbert Herbert Hoover (1874--1964) </Td> <Td> </Td> <Td> 000000001929 - 03 - 04 - 0000 Mar 4, 1929 </Td> <Td> 000000001933 - 03 - 04 - 0000 Mar 4, 1933 </Td> <Td> 7003146100000000000 ♠ 4 years, 0 days </Td> </Tr>

What is the role of the republican party