The contest for the seat held by Sen. Jon Tester, a Montana Democrat, is one of the potentially close 2012 races that could ultimately decide whether Democrats maintain control of Congress' upper chamber.
As such, the battle is attracting attention from outside groups hoping their financial assistance will make a difference for both the first-term Democrat and his Republican challenger, Rep. Denny Rehberg, the state's sole House member and a former lieutenant governor.
Mitt Romney starts the week having undergone a transformation.
For almost a year, he tried to portray himself as the grown-up in the Republican race for the presidential nomination. Now, over the course of two debates and countless Florida campaign stops, the buttoned-up businessman is showing that he can get tough.
This shift has upended the yin-yang dynamic that has been playing out for weeks between the passionate, fiery Newt Gingrich and the staid, steady Romney.
One of the guests in the congressional gallery at last week's State of the Union address was Roxana Delgado, an advocate for soldiers returning home with traumatic brain injuries. Her husband, an army sergeant who NPR profiled in June, 2010, had been dramatically affected by the concussion he received from a roadside blast in Iraq.