By Marie Horrigan, CQ Staff

New Mexico faces an unusual total turnover of its U.S. House delegation, with all three members — Democrat Tom Udall and Republicans Heather A. Wilson and Steve Pearce — running for the Senate seat left open by retiring Republican Pete V. Domenici . And while each of the three districts is staging an open house for open-seat candidates, the most intense scramble may be occurring in the Albuquerque-based 1st, a partisan battleground district of long standing.

The state’s preliminary candidate filing deadline passed Tuesday, and seven major-party candidates — five Democrats and two Republicans — are in the race to succeed Republican Wilson, who won a hard-fought and narrow re-election victory in 2006 over Democrat Patricia Madrid, then New Mexico’s attorney general.

Democratic strategists are again targeting the 1st, a heavily Hispanic district that favored Democrat John Kerry over President Bush by a 3 percentage-point margin. The party’s voters in the June 3 primary may choose among a mix of politically experienced candidates and relative newcomers. CQ Politics rates the race as No Clear Favorite.

One recent officeholder, former New Mexico Secretary of State Rebecca Vigil-Giron, announced Feb. 2 she would run for the Democratic nomination, emphasizing her background as an 11th generation New Mexican. Other well-known figures seeking the nomination are former Albuquerque Councilman Martin Heinrich and former state Health Secretary Michelle Lujan Grisham.

Vigil-Giron and Lujan Grisham both are Hispanic. Christine Sierra, a professor of political science at the University of New Mexico in Albuquerque, said this could boost them in a district in which Hispanics make up well more than two-fifths of the population. But they could split the Hispanic vote, which also will be pursued by Heinrich, the best-known among the non-Hispanic white candidates. Heinrich entered the race in April, before Domenici announced his retirement plans and incumbent Wilson shifted her sights to the Senate race.

Also seeking competitive status in the contest are Democrat Robert Pidcock, an Albuquerque lawyer, and Jessica Wolfe, a 28-year-old former aide to highly popular New Mexico Democratic Gov. Bill Richardson . Wolfe, a 2002 graduate of Tennessee’s Vanderbilt University, was a special assistant for Cabinet affairs in Richardson’s administration and, more recently, worked in Richardson’s short-lived campaign for the 2008 Democratic presidential nomination.

Year-end reports indicate Heinrich led the Democratic pack in fundraising, aided in part by his early start. By Dec. 31, Heinrich raised $465,000 and had $277,000 left on hand. Lujan Grisham, the other Democrat who filed a campaign finance report, had raised $116,000 and had $96,000 on hand. The other candidates will be required to file their initial reports, for the first quarter of 2008, by April 15.

The choice for Republican voters is less complicated, as there are only two candidates: Bernalillo Sheriff Darren White and state Sen. Joe Carraro, another relatively late entry. Of the two, Sierra described White as the “more formidable candidate.”

White raised $213,000 for the race in 2007 and has received strong support from the state Republican Party organization and from Domenici, who has helped him in fundraising.

It is not certain that all of the candidates who applied to run will make it to the June 3 primary ballot. The Feb. 12 filing deadline was for candidates who want to compete in a district’s nominating convention, which by law must be held before the third Sunday in March (the 16th this year).

Any candidate who receives at least 20 percent of delegates’ votes at the district convention qualifies automatically for the primary. But candidates who fail to win automatic ballot access can get their names on the ballot by submitting twice the number of signatures required for their initial filing either 10 days after the convention or by March 18th, whichever is later.