The hard-fought and at times bitter battle for the Republican Senate nomination in New Mexico between Reps. Steve Pearce and Heather Wilson concludes with today’s voting.

But for Republicans, an even tougher fight awaits in the form of the presumptive Democratic Senate nominee, Rep. Tom Udall, who has no primary opponent.

Udall, a former two-term state attorney general with great name recognition and a solid reputation, enters the general election to succeed Sen. Pete Domenici (R) with almost $3 million in the bank and a statewide campaign that is already up and running. With Democrats ascendant nationally, the backing of popular Gov. Bill Richardson (D) at home and the Republicans struggling to defend almost twice as many Senate seats as the Democrats, Udall enters the race as the clear favorite.

All polling conducted on potential matchups with Pearce and Wilson confirms as much. But the Udall campaign claims the Congressman isn’t measuring the drapes in his new Senate office just yet.

“Tom Udall is not taking anything for granted,” said campaign spokeswoman Marissa Padilla. “He’s been working since the day he announced, and we’re not going to stop until Election Day in November.”

Brian Sanderoff, an independent pollster based in Albuquerque, suggested that Udall’s caution is warranted.

Sanderoff described Udall as a strong candidate who will be difficult to beat in November, whether his GOP opponent is Pearce or Wilson. But the Research & Polling, Inc. pollster said Udall’s high favorable ratings are due in part to the fact that he hasn’t had to run a competitive race in several years.

“If he had been challenged 10 times and was still ahead [in the Senate race] by 10 points, that’s one thing. But he hasn’t been challenged — lately,” Sanderoff said. “Udall’s favorability has nowhere to go but down.”

In the race between Pearce and Wilson, Pearce had a 6-point lead, according to a poll conducted last week for the Albuquerque Journal by Sanderoff. The survey had Pearce ahead of Wilson among likely GOP primary voters 45 percent to 39 percent, with 16 percent undecided.

However, the May 27-29 survey was completed before Friday, when Domenici endorsed Wilson, whom he originally recruited to run for the Albuquerque-area 1st district seat that she is vacating to run for Senate. Domenici, known in New Mexico political circles as “St. Pete,” still carries enormous cache throughout the state.

It is believed that Domenici’s endorsement, combined with Wilson’s get-out-the-vote program — thought to be superior to Pearce’s by some Republican strategists monitoring the race — could have helped her turn the tide in the closing days of the campaign. Wilson, who has repeatedly won close contests in her competitively drawn 1st district, has heavily targeted absentee and early voters in the Senate contest.

A recording of Domenici urging voters to support Wilson in today’s election began hitting Republican households throughout the state via telephone on Monday. Sanderoff said Domenici’s move to back Wilson had not caused him to reassess the validity of the poll he conducted for the Journal.

According to a Republican operative based in New Mexico, Domenici’s endorsement could help Wilson the most among the 16 percent of GOP primary voters who were undecided in the Journal poll — and among all Republican voters who live in Udall’s heavily Democratic, Santa Fe-area 3rd district. There, the Journal poll had Pearce leading Wilson 46 percent to 37 percent.

Domenici’s electoral performance in the 3rd district has been unparalleled over the years among other Republicans running for statewide office.

“Momentum is going [Wilson’s] way,” the New Mexico-based Republican operative said. “But by the numbers, Pearce is probably still ahead going into Election Day.”

According to the Journal poll, Wilson led Pearce in the 1st district, 57 percent to 27 percent, although Pearce had a 64 percent to 23 percent lead over Wilson in his solidly conservative, southern New Mexico 2nd district. The survey had an error margin of 4 points.

Pearce beat Wilson by 9 points in voting by state GOP activists at the pre-primary New Mexico Republican Party nominating convention held in mid-March. The Pearce team was confident that the Congressman would win that contest, and his campaign is equally confident that he will finish on top when the polls close this evening.

Pearce has hammered Wilson on her floor votes on issues ranging from government spending to border security to abortion, arguing that he is the real conservative in the race. In a potential race against Udall, Pearce campaign spokesman Brian Phillips said, the Congressman plans to make the same argument — that Udall, despite his record during his years as attorney general for cracking down on sex offenders and curbing what had been a serious statewide problem with drunken driving, is too liberal for most New Mexico voters, both Democrats and Republicans.

“The strategy we had on June 2 will be the same on June 4,” Phillips said.

Although Pearce was significantly outraised by Wilson in the primary campaign, the key question moving forward in the general election, should the Congressman win today, is: Can he raise enough money to sufficiently broadcast a message that will include an attempt to redefine Udall?

Phillips predicted Pearce would have “enough.” He said Pearce has no plans to tap his personal wealth, which runs into the tens of millions of dollars, to fill the gap if he has trouble competing with Udall on the fundraising front.

One Republican fundraiser based in Washington, D.C., said Pearce might find contributions hard to come by in the nation’s capital, in part because Domenici has spent months telling people that only Wilson could beat Udall in the general election. But Pearce, who previously owned an oil services company, has historically been supported financially by energy companies, and he could find that to be fertile territory.

Financial sources that are strongly committed to GOP policy goals will play in the race regardless of who wins the primary, the fundraiser said, although the Republican Party’s minority status on Capitol Hill has made fundraising harder than it was just two years ago.

Meanwhile, Wilson strategists are bullish about the Congresswoman’s prospects, crediting her performance in the past two debates, and, most of all, the Domenici endorsement, for their optimism.

Wilson campaign spokeswoman Whitney Cheshire noted that in the 2006 1st district general election race, Wilson trailed her opponent by 6 points in the last Albuquerque Journal poll conducted before Election Day, before going on to win the race by 900 votes.

“We believe that Domenici’s endorsement is moving lean-Pearce and undecided voters to Heather Wilson,” Cheshire said on Monday. “We believe the race is a dead heat right now.”