American Conservative Union head: 'Time for conservatives to unite' behind Romney

Cardenas worked for Romney's campaign in 2008 and introduced him at this February's Conservative Political Action Conference, but as head of the ACU had remained neutral in the race — until now.

He joins House Majority Whip Kevin McCarthy (R-Calif.), former Florida Gov. Jeb Bush (R) and Sen. Mike Lee (R-Utah), a Tea Party favorite, in recent Romney endorsements.

There is a push by some in the GOP to rally around Romney and end the primary soon so as to avoid additional intra-party bloodletting. Other conservative Republicans who've praised Romney in recent days include Sens. Pat Toomey (R-Pa.) and Jim DeMint (R-S.C.).

This post was updated at 11:30 a.m.

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