Gingrich, who was U.S. House speaker in the 1990s, has won primaries in Georgia and South Carolina and is seeking other Deep South wins in Mississippi and Alabama.

A political action committee called Winning Our Future aired a Mississippi radio ad that said: “America needs Newt Gingrich to beat Barack Obama. On today, make the media eat their words. No more Pennsyl-Massachusetts-vania-fulla-soundbites-and-whining. Elect a man who speaks the same in Jackson as he does in Washington.”

Mark Wrighton, a political scientist and associate dean for undergraduate programs and assessment at the University of Southern Mississippi, said Romney can be satisfied with second- or third-place finishes in Mississippi and Alabama.

“We’re going to be asking ourselves tomorrow night, did Sen. Santorum jump over the bar high enough? Did Speaker Gingrich jump over his bar high enough?” Wrighton said Monday. “It’s all about the expectations game.”

•  In the 2nd District, which stretches along the Mississippi River, through the Delta and into Jackson, Democrat Bennie Thompson of Bolton, first elected to the seat in 1993, is challenged today by Heather McTeer, who recently completed two terms as mayor of Greenville. The Democratic nominee advances to the November general election to face Republican Bill Marcy of Vicksburg and independent Cobby Mondale Williams of Canton.

•  In the central 3rd District, Republican incumbent Gregg Harper of Pearl faces one primary challenger, Robert Allen of Sturgis. In November, the Republican nominee will face Democrat Crystal Biggs of Florence. Harper first won the seat in 2008.

• In the Senate race, Republican incumbent Roger Wicker of Tupelo faces two GOP primary opponents, E. Allen Hathcock of Stewart and Robert Maloney of Madison. Wicker was appointed to the Senate in December 2007 by then-Gov. Haley Barbour, after Trent Lott stepped down.

That appointment gave Wicker almost a year in the Senate before a special election to fill the final four years of the six-year term Lott started. Wicker defeated Democratic former Gov. Ronnie Musgrove in the 2008 special election.

The three people seeking the Democratic nomination for Senate this year are Albert N. Gore Jr. of Starkville, Will Oatis of Silver Creek and Roger Weiner of Clarksdale. The Reform Party’s Shawn O’Hara and the Constitution Party’s Thomas Cramer Party will be on the November ballot.