Romney's decision comes after a big disappointment in the Super Tuesday primaries, and it gives John McCain a virtual lock on the republican nomination.
Mitt Romney was John McCain's chef rival. McCain is now the obvious beneficiary, if Romney's supporters don't all line up behind Mike Huckabee.
Mitt Romney told a conservative conference in Washington D.C. he must end his campaign for the good of the party.
"If I fight on in my campaign all the way to the convention, I would forestall the launch of a national campaign and make it more likely that senator Clinton or Obama would win," said former Massachusetts Governor (R) Mitt Romney.
John McCain told the same audience he knows he's upset some conservatives. McCain smiled though, and promised he got their message.
"I have pledged that it would be among my highest priorities to secure our borders first to secure our borders first," said Senator John McCain (R) Arizona.
Senator McCain has been attacked by conservative pundits for not being conservative enough.
On Thursday, conservative talk show host Rush Limbaugh reacted to Romney's departure by saying he's considering raising money for Hillary Clinton. But not because he supports her, but because he wants to see her get the nomination feeling she would be easier for McCain to beat.
A more moderate Republican, governor Schwarzenegger says Romney's withdrawal makes sense.
"The distance between senator McCain and him was so enormous that mathematically it just didn't pencil out anymore," said Gov. Arnold Schwarzenegger (R) California.
Former California Secretary of State Bill Jones is chairman of McCain's California campaign.
"Clearly with the votes that we received and the delegates the senator is on his way to the nomination," said McCain campaign state chairman Bill Jones.
Jones says McCain isn't taking the nomination for granted, but he also believes Mike Huckabee won't be able to catch up.
ABC7 Political Analyst Bruce Cain expects republican party activists to increase pressure on Huckabee to drop out.
"Remember the Republicans are way behind the democrats in fundraising they're not getting, they're not getting as many people showing up they're not getting the kinds of money the democrats are getting so the longer this goes the more republican money has to be spent on the nomination," said ABC7 political analyst Bruce Cain, Ph.D.
In addition to the money, there's the message problem.
Against Huckabee, McCain is touting his conservative credentials talking about being pro-life and appointing conservative judges.
But if McCain gets the nomination, those positions could hurt with moderates and independents in the November election.
