premise: The US Congress ends the year divided as never before, over issues ranging from the Iraq war, to immigration reform and a series of ethics scandals.
  Many political observers now say relations between ruling Republicans and rival Democrats on Capitol Hill are the worst they have ever seen. They predict the wrangling will not improve as the United States heads toward mid-term elections in November.
  "People naturally disagree about who is responsible for the partisan tone and tactics in Washington DC these days, but most agree on this -- its worse, its more intense, and its nastier," said Nancy Roman, vice president at the New York based Council on Foreign Relations.
  Much of the bickering is over Iraq, which has caused sparring between the two political parties and among factions within them.
   What issues are part of the wrangling on Capitol Hill?
hypothesis: immigration reform