The Democratic activists pushing for the confirmation of President Obama’s Supreme Court nominee measure their efforts by the numbers: more than 400 newspaper editorials, several dozen live protests and 1.5 million petition signatures urging Republican senators to take up Merrick Garland’s ­nomination.

But this, too, can be measured: As of Monday, 52 senators oppose a hearing for Garland, let alone an up-or-down vote, before voters choose Obama’s successor in November.

The all-out Democratic advocacy blitz during the two-week recess ending Monday has produced no discernible impact in the arena that really matters: the Senate Republican caucus.

Only two of 54 Republican senators say they favor hearings. And two other senators who previously supported hearings reversed their positions under pressure from conservative activists, indicating that Senate Majority Leader Mitch McConnell (R-Ky.) has so far been extremely successful in holding together the Republican ­blockade.

In declaring progress, Democrats are seizing on polling data, media coverage and the willingness of at least 16 Republican senators to meet informally with Garland in their offices.

“It couldn’t be clearer,” Sen. Charles E. Schumer (D-N.Y.) said in a Friday call with reporters. “The public is overwhelmingly on our side. Every day, voters grow more frustrated with Republican obstruction and more terrified by the prospect of Donald Trump picking the next Supreme Court justice.”

Now, with senators back in Washington, the pressure campaign is moving to a new phase with Democrats hoping to parlay Garland’s meetings into Republican action. This week, Republican Sens. John Boozman (Ark.) and Susan Collins (Maine) are set to sit down individually with Garland, as are nine Democratic senators.

Democrats are hoping for a reprise of his first meeting with a Republican senator — last week with Mark Kirk of Illinois, who, while seated next to Garland, declared his colleagues “closed-minded” for snubbing him.

But conservatives are warning not to expect much from the courtesy meetings, saying that they are just that.

“They’re confusing courtesy with weakness on the part of Republicans, and that’s not fair at all,” said Carrie Severino, chief counsel for the Judicial Crisis Network, which is coordinating outside support for the ­blockade.

“There was never a hard-line Republican position on do we meet with Garland or don’t we,” Severino added. “The discussion is do we have hearings and do we have a vote? . . . And that has held. There is an incredible amount of unity.”

Republican leaders have not explicitly issued instructions on how to stage-manage the sit-downs, but one GOP aide said the playbook is clear: “Have your boss go out, shake hands, bring him in conference room, and after it’s over, say what he’s been saying over and over again.”

With the exception of Kirk and Collins — moderates who frequently break with the party line — the Republicans who have agreed to meet with Garland have said they intend to use the meetings to explain their reasoning for not moving forward with confirmation.

Others who have strayed from that orthodoxy have been pulled back into line. Days after leaving Washington last month, Sen. Jerry Moran (R-Kan.) told a Rotary Club that senators “have the responsibility to have a hearing, to have the conversation and to make a determination on the merit.”

Once that statement circulated around Washington days later, conservative groups such as the Judicial Crisis Network, the Tea Party Patriots and others pounced, with some suggesting he could face a challenger in the August Republican primary.

Moran backed away from his position soon after, and on Friday, he renounced it completely, with his office issuing a statement declaring that, after a review of the nominee’s record, he “didn’t need hearings to conclude that . . . Garland [is] unacceptable to serve on the Supreme Court.”

One major activist group, FreedomWorks, as of Friday had tracked more than 28,000 emails its members had sent to Moran’s office demanding he withhold action on any nominee.

“We said, ‘We’re going to make him our example,’ ” said Jason Pye, the group’s communications director. “In terms of our statements to the media, in terms of our activism, in terms of whatever else we can do, we wanted to show him how wrong he was and how he is on the other side of the conservative grass roots.”

Another Republican senator, Lisa Murkowski of Alaska, underwent a similar reversal. Four days after news of Antonin Scalia’s death, she told a group “the nominee should get a hearing.” Later, she issued a statement saying she “respects the decision of the chair and members of the Judiciary Committee not to hold hearings on the nominee.”

Several polls have shown that roughly two-thirds of voters nationally want to see congressional action on a Garland ­nomination.

And Democrats, including some of Obama’s top aides, say they are confident that Republicans will eventually relent when they confront public opinion in favor of Garland’s confirmation and realize the blockade threatens their tenuous Senate ­majority.

They have sketched out ways to keep the pressure on with lawmakers back in Washington. Sen. Elizabeth Warren (D-Mass.), who commands unmatched attention from her party’s progressive wing, is set to conduct a grass-roots organizing call Monday. Activists will continue hitting the streets in states represented by key Republican senators. And on Thursday, Obama will deliver an address on the Supreme Court at the University of Chicago Law School, where he was a professor before entering elected office.

Brian Deese, the White House adviser who is leading the confirmation push, said at a Politico breakfast event Friday that Obama is “committed to trying to make the case in a straightforward way that the Supreme Court needs to stay above politics” and said he felt “very good” that Garland would ultimately be confirmed.

“Our prospects before the nomination were written off 100 percent,” Deese said. “Now we’re 15 days in, and it turns out that a growing number of Republicans are willing to sit down, so we’re going to stay focused on the process.”

Democrats are not the only ones subscribing to the slippery-slope theory. Pye said the senators who have agreed to sit down with Garland are “playing with fire.”

“They’re playing right into the hands of the White House, whether they realize it or not,” he said. “Meetings lead to hearings, which lead to votes.”

Schumer, on Friday, offered the Democratic take on that notion: “Inches will turn into feet, feet will turn into miles, and hopefully Judge Garland will turn into Justice Garland in the coming months.”