Tea Partier and former Nevada Senate candidate Sharron Angle (R) has endorsed conservative businessman Greg Sowards (R) in a three-way New Mexico primary.

"Greg Sowards is our only opportunity to advance conservatism," Angle wrote in an email to his supporters.

Sowards faces an uphill battle against two top-tier foes. Former Rep. Heather Wilson (R-N.M.), a centrist, is considered the front-runner in the race, while Lt. Gov. John Sanchez is running to her right. Washington-based outside conservative groups dislike her voting record but are hesitant to back Sanchez over some more centrist stances he's taken on immigration.

That leaves Sowards, a self-funding candidate who could play spoiler to Sanchez. The race has not been polled recently, but mid-summer polls had Wilson near 50 percent support. If Sowards gains enough traction, he could keep Sanchez from mounting a real challenge to Wilson, giving her the nomination.

Angle, who lost her 2010 bid to unseat Senate Majority Leader Harry Reid (D-Nev.), is a controversial figure for some hard-right stances — and for failing to convert what many Republicans saw as a golden opportunity to beat the Democratic leader.

The Democrats in the New Mexico Senate race are Rep. Martin Heinrich and State Auditor Hector Balderas. The candidates are running to replace the retiring Sen. Jeff Bingaman (D-N.M.).