Washington: Mississippi incumbent Thad Cochran was fighting for his political life in a Republican runoff for his US Senate seat Tuesday, seeking to repulse a surging conservative challenger bucking the party establishment.
A series of primary races are similarly pitting political veterans against relative outsiders, including key contests in Oklahoma, New York and Colorado, as the fields are sown for the congressional mid-term elections in November.
Republicans are widely expected to retain control of the House of Representatives, and with President Barack Obama`s Democrats struggling to hold the Senate, the GOP is pouring efforts into this year`s campaigns in hopes of winning both chambers of Congress.
Such an outcome would all but doom any legislative agenda Obama would want to achieve in his final two years in the White House.
Tuesday`s main event is in the southern Gulf Coast Republican stronghold of Mississippi, where 76-year-old Cochran, one of the old-guard gentlemen of the Senate, was forced into a runoff this month by state senator Chris McDaniel, a radio talk-show host backed by the anti-tax, small-government Tea Party movement.
All eyes are on the state to see if veteran Cochran goes down, much like House Majority Leader Eric Cantor lost his seat earlier this month to a little-known conservative professor in their Virginia primary.
That outcome sent shock waves through Washington, and empowered Tea Party-backed candidates angling for their own upsets against Republican incumbents.
With anti-Washington animosity sky-high, members of the GOP establishment have rushed to Cochran`s rescue, including 2008 presidential nominee Senator John McCain who hailed Cochran`s record on military issues.
McCain`s running mate, Sarah Palin, by contrast, campaigned in Mississippi last month for McDaniel.
The race has emerged as one of the most expensive primaries ever, with outside groups pouring money into both campaigns.
Cochran, nicknamed the Senate`s "King of Pork," has been accused of squandering taxpayer money by funneling millions of dollars per year in earmarks to his state, something McDaniel has seized on while campaigning.
"This is pretty simple," McDaniel reportedly wrote in a fundraising email.
"If you think we should keep the same guys in office that supported these outrageous spending sprees, then listen to John McCain and support Thad Cochran."
In New York, veteran Democrat Charlie Rangel faces the toughest re-election fight of his 22-term career, in a rematch of the 2012 primary against state senator Adriano Espaillat.
Rangel, 84, leads in polls, but should he lose it would mark the end of an era in New York politics.
In Oklahoma, two-term Republican congressman James Lankford is favored to win retiring Senator Tom Coburn`s seat, but he faces strong opposition from T.W. Shannon, an African-American member of the Chickasaw Nation and former speaker of the statehouse.