New Mexico doesn't look like much of a swing state in the presidential election, according to a recent poll of likely voters last week, but the U.S. Senate race might be a nail-biter.

And even though Democratic President Barack Obama is polling strongly here, the latest Rasmussen poll also shows that Republican Gov. Susana Martinez is very popular -- even among registered Democrats.

According to the poll of 500 "likely voters," conducted Feb. 14, Obama would handily defeat both Rick Santorum (55 percent to 37 percent) and Mitt Romney (55 percent to 36 percent.)

The names of other Republicans still in the race, Newt Gingrich and Ron Paul, were not included in the survey. Neither was former New Mexico Gov. Gary Johnson, who is seeking the Libertarian Party nomination.

Rasmussen's numbers are slightly better for Obama than the last Public Policy Polling survey taken in the state in mid-December. According to that poll, Obama was beating Romney 53 percent to 38 percent. Santorum wasn't included in that poll. Obama was leading other Republican candidates by similar margins in the PPP match-ups.

PPP is a Democratic polling company.

The Rasmussen poll shows, however, that the Senate race is a virtual toss-up. Democrat Martin Heinrich has a 2 percent advantage over Republican Heather Wilson. When Hector Balderas is named as the Democratic candidate, he and Wilson are tied at 44 percent each.

As for the governor, according to last week's poll, 66 percent said they approve of her performance -- and half of those "strongly" approve. Thirty-three percent disapprove of Martinez's performance. Of those, 21 percent "strongly" disapprove.

Her approval among Republicans is 94 percent. More surprising is that a majority of Democrats, 54 percent, approve of her performance, according to the poll.

The margin of error is 4.5 percentage points.

UPDATE: 8:33 am. There was a typographical error in Gov. Martinez's approval rating in a previous version of this article. That has been corrected in the text.

Contact Steve Terrell at 986-3037 or sterrell@sfnewmexican.com. Read his political blog at roundhouseroundup.com.