Perhaps no state this year will offer a more wide-open field for both parties than New Mexico, a state that has long been a battleground in presidential politics. But thanks to a key retirement this year, four of the state's five seats in Congress are up for grabs, and Democrats and Republicans are focusing on the state early to gain the upper hand.

When Senator Pete Domenici, who has served in the upper chamber since 1972, announced he would forgo a bid for a seventh term this year, the ensuing scramble has thrown all three of the state's members of Congress into a mad dash for a rare opportunity to move to the upper chamber.

While Democrats feel all but certain they will retake the seat, the state truly favors neither party. Domenici and his junior colleague, five-term Democrat Jeff Bingaman ("junior" being an extremely relative term), have not faced serious competition in a generation, but presidential contests have been decided by razor-thin margins. Al Gore won the state by 365 votes in 2000, out of more than 550,000 cast, and President Bush took the state by 6,000 votes in 2004.

Republicans face the difficult task of wading through what is likely to be an expensive and bloody primary, as Roll Call's David Drucker writes. As Republican Reps. Heather Wilson, of the Albuquerque-based First District, and Steve Pearce, whose Third District covers the southern portion of the state, fight it out, Democratic Rep. Tom Udall will not face a competitive primary and will likely meet a wounded Republican in the fall.

Udall is already in good position. A November poll conducted for his campaign shows him leading both Wilson and Pearce by wide margins. And while the two Republicans will be forced to spend heavily from their bank accounts to win the June 3 primary, Udall can stockpile cash and build on the lead he already has. Through December, Udall held $1.7 million in the bank, compared with just under $1.1 million for Wilson and $819,000 for Pearce.

The Senate race is hardly the GOP's only worry, though. None of the state's three open seats are out of reach for Democrats, and with the aid of big national dollars, the party could conceivably take all three Congressional seats along with Domenici's slot in the Senate. Udall's seat and Pearce's seat favor their respective parties by about equal margins, though Democrats have found more success recruiting in Pearce's district than Republicans have in Udall's.

It is New Mexico's First District where the biggest battle will be fought. Based in the state's largest city, Wilson never had an easy bid for re-election after winning her initial contest, a special election, with just 45% of the vote. Democratic presidential nominees have won the seat narrowly in both 2000 and 2004, making recruiting the right candidate key to taking over.

Three strong Democrats are fighting for the nomination, including Albuquerque City Councilman Martin Heinrich, former Cabinet officer Michelle Lujan Grisham and former Secretary of State Rebecca Vigil-Giron. Republicans, meanwhile, think Bernalillo County Sheriff Darren White, the likely GOP nominee, is one of their strongest recruits in the country. Sheriffs willing to run good campaigns have a tendency to win even in districts that don't necessarily favor their parties, as Washington State Republican Dave Reichert and Indiana Democrat Brad Ellsworth have shown.

In Pearce's Second District, a number of Republicans are seeking the nomination, including Earl Greer, the chair of the Sierra County Republican Party, Monty Newman, the Mayor of Hobbs, Aubrey Dunn, a retired banker and rancher, and wealthy restauranteur Ed Tinsley. The winner will likely face either Dona Ana County Commissioner Bill McCamley or former Lea County Commissioner Harry Teague. Democrats hold out hope that another wave election could improve their chances in what is ordinarily a GOP district.

The northern Third District looks like the only contest in which the incumbent party is highly likely to keep control. State Public Regulation Commission chairman Ben Lujan, Santa Fe County Commissioner Harry Montoya, real estate developer Don Wiviott and former Indian Affairs Secretary Bennie Shendo are the district's leading Democratic hopefuls. The district is majority-minority, in which 19% of the electorate is Native American and 36% has Hispanic heritage. Republicans will likely nominate attorney Marco Gonzales.

From Domenici's seat to Congressional races around the state, New Mexico will offer some of the best opportunities for Democrats this year. The state is also one of the few examples where Republicans have recruited well, thanks in large part to White, running to replace Wilson. If Republicans come out of 2008 maintaining control of at least one Congressional seat and Domenici's Senate seat, the party will likely have a better year than many expect. But if Democrats sweep, or take three of the four contests, November will be a bad month for Republicans around the country.