WASHINGTON — The bison has become the official national mammal of the United States under legislation signed into law by President Barack Obama on Monday.

By Kevin Freking, Associated Press

WASHINGTON — Democrats plan to use Senate consideration of the Keystone XL oil pipeline to get Republicans on the record about climate change and to resurrect parts of a bipartisan energy efficiency bill doomed by pipeline politics last year.

By Dina Cappiello, Associated Press

I’ve spent so many years talking about lame ducks in the White House and Congress, and it’s never occurred to me to find out what the heck it means.

By Gwen Ifill

A bipartisan group of senators have worked out a potentially critical compromise for the immigration reform bill. Reform supporters said they had met demands for greatly expanded policing of the border with Mexico. Ray Suarez talks with two lawmakers shaping…