Two front-runners in the race to succeed retiring Sen. Jeff Bingaman (D-N.M.) have emerged, but all signs indicate a rough road to Election Day.

The leaders in the race in terms of polling and fundraising are Democratic Rep. Martin Heinrich, who is currently serving his second term representing the state's 1st District, and his predecessor, Republican Heather Wilson, who gave up the House seat for an unsuccessful run for the Senate against now-Sen. Tom Udall, a Democrat. Wilson lost her party's primary nomination in that race.

Also running for the Democratic nomination are state auditor Hector Balderas and Albuquerque political activist Andres Valdez. On the Republican side, Lt. Gov. John Sanchez and Las Cruces businessman Greg Sowards are also seeking their party's nomination.

Jennifer Duffy, the senior editor of The Cook Political Report, said that "both sides ended up with pretty strong candidates and you are going to end up with a pretty good general election."

Heinrich received strong early support from the national party when Democratic Senatorial Campaign Committee Chairwoman Patty Murray (D-Wash.) said that his "decision to enter the race really confirms that Democrats have a very strong field and he's doing a great job."

Heinrich also received early backing from organized labor.

Meanwhile Wilson, who most recently headed the transition team for the Republican Gov. Susana Martinez, was endorsed by former Republican Sen. Pete Domenici and former Republican Reps. Manuel Lujan and Bill Redmond.

And while Martinez has said she will not endorse in the primary, she appears to have thrown her support behind Wilson by limiting her lieutenant governor's duties since he announced his intention to run.

In an announcement from her office, the governor said, "It is Lt. Governor Sanchez's decision to pursue what he believes is a once-in-a-lifetime opportunity to run for the Senate. However, it is my responsibility to keep my word to the people of New Mexico by pursuing the reform agenda I promised and delivering the results they deserve. To prevent this race from becoming a distraction, Lt. Governor Sanchez will not be given responsibilities in my administration beyond the select few provided for in the state Constitution."

Environmental issues

Among the two front-runners, Heinrich is considered far stronger on the environment. He received a 100 percent lifetime rating from the League of Conservation Voters, which rates members on their environmental votes. Wilson received a 15 percent lifetime rating from LCV, and the group named her to its "Dirty Dozen" list, which highlights for defeat lawmakers with particularly abysmal environmental records.

Additionally Heinrich served as the president of Albuquerque's City Council where he pushed for development of wind and solar power. He was also appointed the state's natural resources trustee.

It was as a city councilman that Scott Wilber, the executive director of the New Mexico Land Conservancy, first interacted with Heinrich.

"He's definitely the person we'd like to see in that position," Wilber said. "He's been very supportive not only of our land trust movement but all of the federal funding programs for land and water conservation."

Leanne Leith, the political director of Conservation Voters New Mexico, said both her organization and LCV have already endorsed Heinrich.

That decision was made even before Balderas entered the race, "based on Rep. Heinrich's exceptional record in Congress," Leith said. She also noted that the "environment has always been a core issue for him."

As for Wilson, Wilber said she is "probably the strongest candidate on the Republican side." He continued, "she seems to be fairly moderate. She has been supportive of a few initiatives in the past."

Whichever politician gets elected, they will have Bingaman's big shoes to fill, especially when it comes to the national renewable energy standard that he has continually pushed.

"I certainly think that whoever replaces him would or should share that dedication since New Mexico has such a potential for renewable energy," Leith said.

A tight race

Overall the race is expected to be tight. Though Bingaman received 71 percent of the vote in 2006, The Cook Political Report rates the race as a toss-up since the political landscape in the Land of Enchantment has changed since then.

In a state with a large Hispanic voting population, Balderas and Sanchez may have an edge. For 2010, the U.S. Census reported that 47 percent of the state's population was of Hispanic or Latino origin.

In a Public Policy Polling survey released at the end of June, Heinrich had a lead over Balderas of 47 percent to 24 percent. But among Hispanics, the race was far tighter with Heinrich ahead 39 percent to 36 percent.

Last month Balderas received the endorsement of former Lt. Gov. Diane Denish. In a statement, Dinesh said that the "Senate needs more leaders like Hector Balderas. Leaders who reject the premise that 'fiscal responsibility' and 'accountability' are Republican words."

The Cook Political Report's Duffy described Balderas as "an interesting candidate" who may have been underestimated by his party.

"In my mind, the jury is still a little bit out. He's jumped the first few hurdles and let's see if he can keep going," she said.

The latest polls show both Wilson and Heinrich ahead.

In a July 19 survey by Magellan Strategies of likely Democratic primary voters, Heinrich led Balderas 52 percent to 19 percent. And in a survey on the same day of likely Republican primary voters, the company found Wilson led 56 percent to Sanchez's 21 percent.

Looking at the front-runners, Duffy described Wilson as "a pretty good candidate" and of Heinrich she said that "Democrats weren't crazy to want him as their standard bearer."

But she said one thing to note is that Heinrich and Wilson as well as Sanchez all share an Albuquerque base that could affect them.

Meanwhile one potential candidate, Republican Rep. Steve Pearce, has not announced whether he is running.

One thing is certain: The money race is sure to grow fiercer. Later this week top Bush adviser Karl Rove is flying in to appear at an Albuquerque fundraiser for Wilson.

As it stands, at the close of the second quarter, Heinrich led the money race, ending the quarter with $709,683 of cash on hand while Wilson had $604,181. Balderas, who announced his campaign in late April, ended the quarter with $370,867 in cash on hand while Sanchez had $246,539.