A second Republican has thrown his hat into the ring to vie for the Senate seat being vacated by retiring Republican Pete Domenici: Oil industry investor and political neophyte Spiro Vassilopoulos.

Vassilopoulos joins Rep. Heather Wilson, who has also declared her candidacy in the Republican primary. However, he believes that the toughest opponent to beat will actually be New Mexico's other Republican House member, Steve Pearce, who looks like a much stronger potential nominee than Wilson.

"Pearce is a fellow oil man and someone I consider to be intellectually honest," Vassilopoulos said. "I have great admiration for his abilities."

In short, this primary could get very crowded, and very soon. And if Wilson was hoping for an easy primary — she was long viewed as a political protégée of Domenici — it doesn't look like it's going to happen.