<P> Lobbyists represent diverse interests and often seek to influence congressional decisions to reflect their clients' needs . Lobby groups and their members sometimes write legislation and whip bills . In 2007 there were approximately 17,000 federal lobbyists in Washington . They explain to legislators the goals of their organizations . Some lobbyists represent non-profit organizations and work pro bono for issues in which they are personally interested . </P> <P> Congress has alternated between periods of constructive cooperation and compromise between parties known as bipartisanship and periods of deep political polarization and fierce infighting known as partisanship . The period after the Civil War was marked by partisanship as is the case today . It is generally easier for committees to reach accord on issues when compromise is possible . Some political scientists speculate that a prolonged period marked by narrow majorities in both chambers of Congress has intensified partisanship in the last few decades but that an alternation of control of Congress between Democrats and Republicans may lead to greater flexibility in policies as well as pragmatism and civility within the institution . </P> <P> A term of Congress is divided into two "sessions", one for each year; Congress has occasionally been called into an extra or special session . A new session commences on January 3 each year unless Congress decides differently . The Constitution requires Congress meet at least once each year and forbids either house from meeting outside the Capitol without the consent of the other house . </P> <P> Joint Sessions of the United States Congress occur on special occasions that require a concurrent resolution from both House and Senate . These sessions include counting electoral votes after a presidential election and the president's State of the Union address . The constitutionally - mandated report, normally given as an annual speech, is modeled on Britain's Speech from the Throne, was written by most presidents after Jefferson but personally delivered as a spoken oration beginning with Wilson in 1913 . Joint Sessions and Joint Meetings are traditionally presided over by the Speaker of the House except when counting presidential electoral votes when the Vice President (acting as the President of the Senate) presides . </P>

What do we call the two year period of time during which congress meets