Conservatives who are normally at odds with Senate leadership are turning out to be important allies in their ongoing campaign to block President Barack Obama’s Supreme Court nominee.

When the Senate recessed in March, conservative groups quickly mobilized activists across the country to reinforce the Republican blockade against Merrick Garland. Organizations like FreedomWorks, Heritage Action, Judicial Crisis Network, and Tea Party Patriots have galvanized support.

For two weeks, the groups ran interference for GOP senators in vulnerable states and corralled wayward Republicans back to the party fold.

So far, it’s worked. Of the 54 Republicans in the Senate, 52 are still standing behind Senate Majority Leader Mitch McConnell, R-Ky., and his promise not to hold confirmation hearings for Obama’s nominee.

“Republicans are holding firmer on this than on practically any other issue we’ve seen in recent history,” said Carrie Severino, chief counsel for the Judicial Crisis Network. That consistency, she told The Daily Signal, should end “claims that there’s some sort of cracks” in the Republican conference.

Outside support has stiffened the GOP’s cohesion.

So far, FreedomWorks has placed more than 1 million phone calls to Republican Senate offices, Tea Party Patriot activists have flooded town halls, and the Judicial Crisis Network has organized a $2 million ad buy.

That grassroots game has done much to blunt the Democrat blitz on the issue. As recently as last Friday, Democrats were pointing to progress. Brian Deese, the White House adviser taking point in the confirmation skirmish, said Garland’s chances of getting confirmed were “very good.”

“Our prospects before the nomination were written off 100 percent,” Deese said at a Politico breakfast. “Before that, they said maybe the president won’t even nominate someone. Now, we’re 15 days in and it turns out that a growing number of Republicans are willing to sit down [with Garland]. So we’re going to stay focused on the process.”

But though 16 Republicans have signaled that they’re willing to meet with the nominee, only two have bucked the party line and support a Senate hearing on Garland. And last week the White House faced another setback: Two other Republican senators reversed their previous support for hearings.

Republican Sens. Jerry Moran of Kansas and Lisa Murkowski of Alaska say they’ll back the blockade.

On Friday, Moran’s office released a statement noting that the judge’s past record on gun rights and deference to administrative agencies “make[s] Garland unacceptable to serve on the Supreme Court.”

His reversal came a week after the senator told constituents in Kansas he “would rather have you complaining to me that I voted wrong on nominating somebody than saying I’m not doing my job.”

That statement to a local Rotary Club ignited a statewide response, said Vicki Sciolaro, a grassroots activist and the 3rd District chairwoman for the Kansas Republican Party. Sciolaro is one of 13,000 Heritage Action Sentinels nationwide who are engaged on the “No Hearings, No Votes” initiative.

“As soon as the grassroots folks heard what [Moran] was doing,” Sciolaro told The Daily Signal, “he got really blasted for trying to push forward the hearings.”

FreedomWorks members dispatched more than 28,000 emails to Moran’s office. Heritage Action distributed flyers at a local town hall meeting and launched a campaign on social media. Tea Party Patriots drafted a protest petition of almost 1,000 names. And the group’s president, Jenny Beth Martin, floated a possible primary challenger.

“I was upset that my friend that we worked so hard to get elected would be entertaining the idea of hearings,” said Sciolaro, who campaigned for the Kansas senator in 2010. She noted that the opposition was organized and vocal on social media.

Now that Moran has reversed course on Garland, Sciolaro says she is proud of the senator “for changing his position and listening to the grassroots—they were screaming pretty loud.”

A similar episode played out in Alaska. There, Murkowski announced that she thought a nominee deserved a hearing shortly after the death of Justice Antonin Scalia sparked the Supreme Court scramble. In a later statement, she noted that she “respects the decision of the chair and members of the Judiciary Committee not to hold hearings on the committee.”

Conservative groups hope the clash in Kansas and Alaska will warn any other wavering Republicans not to jump ship. Martin argues that the grassroots helped Republicans take control of the Senate “precisely for this moment.”

“I hope they remember that’s why they’re in the majority,” she said. “They’re doing their job by standing up for the Constitution and not rubber-stamping everything the president wants.”