As voters head to the polls Tuesday for primaries in Alabama, Mississippi and New Mexico, here is a brief overview of stories to watch:

Alabama’s 2nd district

Heralded GOP recruit Martha Roby needs a strong showing Tuesday night to erase any doubt that she is the right candidate to take on freshman Rep. Bobby Bright (D) in a conservative district that House Republicans must win if they are going to make serious gains in November. Roby was one of National Republican Congressional Committee Chairman Pete Sessions’ (Texas) first recruits early in the 2010 cycle, and she was one of the first 10 challengers to be named to the committee’s vaunted “Young Guns” program. But Roby’s campaign has been marked by an underwhelming fundraising effort and raised the question of whether the Montgomery city councilwoman is ready for the big leagues. After the defeat of fellow Young Gun Vaughn Ward in Idaho’s 1st district Republican primary last week, anything less than an outright victory by Roby will probably be seen as another blow to the national party. Tea party activist Rick Barber seems the most likely candidate to force a July 13 runoff with Roby if one is required in the four-way race, but state Board of Education member Stephanie Bell is also a contender.

Alabama’s 5th district

Party-switching Rep. Parker Griffith (R) is fighting for his political life, just over five months after abandoning the Democrats. GOP leaders were quick to embrace Griffith after his switch even though they spent more than half a million dollars on independent expenditures during the 2008 cycle trying to elect businessman Wayne Parker to the northern Alabama seat. But Parker, local party leaders and tea party activists haven’t been so quick to embrace Griffith. The Congressman’s top Republican primary challenger is Madison County Commissioner Mo Brooks, whom Parker has endorsed. With a third candidate in the race, the contest seems likely to head to a runoff. But if Griffith isn’t close to the 50-percent mark Tuesday night it’s hard to see where he’ll pick up the votes to win the nomination by the time the July 13 runoff rolls around.

Alabama’s 7th district

The race to replace Rep. Artur Davis (D) in this safely Democratic district also appears headed to a July runoff. The top three candidates are attorney Terri Sewell, Jefferson County Commissioner Shelia Smoot and state Rep. Earl Hilliard Jr. Smoot, a local radio talk show host and Hilliard, the son of the district’s former Congressman, had the highest name identification entering the contest, but Sewell has flooded the district with campaign ads after vastly outraising her opponents. Sewell has earned the backing of the well-funded, pro-abortion-rights group EMILY’s List, while Hilliard picked up a notable endorsement from the Congressional Black Caucus political action committee.

Mississippi’s 1st district

State Sen. Alan Nunnelee (R) is another NRCC Young Gun trying to avoid a runoff against a challenger with tea party support in a conservative district that national officials view as a top takeover priority in November. Nunnelee has done a decent job on the fundraising front and has institutional support in the state, but it may not be enough to keep him from heading to a June 22 race against former Eupora Mayor Henry Ross (R), who has put $75,000 of his own money into the race and seems to be generating grass-roots enthusiasm at the right time.

New Mexico

Republicans seem all but certain to select former Rep. Steve Pearce (R) to try to win back his old seat in the 2nd district from freshman Rep. Harry Teague (D). In the state’s other competitive district, former state party Vice Chairman Jon Barela (R) has no competition for the honor of taking on Rep. Martin Heinrich (D) in the fall.