Washington (CNN) -- Another major conservative figure backs Mitt Romney. His voice joins a growing chorus of major names in the Republican Party calling for the divisive GOP nomination battle to come to an end.
On Friday, House Budget Committee Chairman Paul Ryan endorsed Romney's bid for the White House, saying, "I believe he is the right person for the job."
The congressman from Wisconsin also called on conservatives to "coalesce" around the former Massachusetts governor, adding, and "I think we're entering a phase where it could become counterproductive if this drags on much longer."
The backing by Ryan, who's popular among fiscal conservatives, caps a slew of endorsements for Romney by top-name Republicans since his victory in the Illinois primary a week and a half ago.
Last week former two-term Florida Gov. Jeb Bush, who many in the party had hoped would launch his own bid for the 2012 nomination, endorsed Romney. Sen. Jim DeMint of South Carolina, considered a kingmaker among tea party activists, all but endorsed Romney. Earlier this week Sen. Marco Rubio of Florida, a rising star in the party, and President George H.W. Bush, a GOP elder statesman, both formally supported the front-runner.
While endorsements often don't matter that much, and that they haven't proven very effective this cycle, these endorsements from such major names in the party add to the perception that Romney is the inevitable GOP presidential nominee, even though he's only about halfway to reaching the 1,144 delegates needed to clinch the nomination. And for a candidate who still has trouble locking in support from tea party supporters and other grassroots conservative activists, the backing from Ryan, Rubio and the words of support from DeMint can only help.
"This is evidence of Mitt Romney transitioning from being the front-runner to the presumptive nominee and will help move the conversation away from intra-party fighting to where it belongs -- Barack Obama's record as president," said Doug Heye, a Republican strategist and former communications director for the Republican National Committee.
The Ryan endorsement is timely for a second reason. It comes four days before Wisconsin holds its primary, which may be the last chance for former Sen. Rick Santorum of Pennsylvania, Romney's main rival for the nomination, to try and change what appears to be the trajectory of the race. New polling out of Wisconsin on Friday by NBC News/Marist indicates Romney with a 7-point advantage over Santorum, with Rep. Ron Paul of Texas and former House Speaker Newt Gingrich far behind.
One GOP strategist thinks Romney's rivals will hurt themselves by staying in the race too long.
"The establishment train has left the station, and Gingrich and Santorum aren't on it. Soon it will be in their interest to surrender their hopeless ambitions for the larger cause," said GOP strategist and CNN contributor Alex Castellanos.
"They are now depreciating assets. From now on, the closer we get to the convention, the more their influence diminishes until they withdraw. My advice: Sell now, while your stock has some value," said Castellanos, who was a top media adviser for Romney's 2008 nomination bid but who is not taking sides this cycle.
That advice for now doesn't seem to be resonating publicly with Santorum, Gingrich and Paul, who all vow to stay in the race till the end.