Washington (CNN) Under pressure from the right, Kansas Republican Sen. Jerry Moran has changed his mind and now does not support holding hearings for President Barack Obama's Supreme Court nominee, an aide told CNN Friday.

The aide said in a statement that Moran made his opposition to Merrick Garland clear in speaking to Senate Judiciary Chairman Chuck Grassley.

"He has examined Judge Garland's record and didn't need hearings to conclude that the nominee's judicial philosophy, disregard for Second Amendment rights and sympathy for federal government bureaucracy make Garland unacceptable to serve on the Supreme Court," the aide said. "Senator Moran remains committed to preventing this president from putting another justice on the highest court in the land."

Grassley confirmed the conversation in a statement.

"Sen. Moran called me about the Supreme Court vacancy," Grassley said. "I'm confident that he's committed to ensuring the American people have an opportunity to make their voices heard during this pivotal election, and that the Senate should consider the nominee submitted by the next president."

The National Review first reported Moran's decision.

Moran's reversal shows how unlikely it is that Republicans will defect from their base, which is furiously opposed to Obama replacing the late Justice Antonin Scalia, who died in February.

Last week, Moran caused a fury among conservatives when he told a town hall gathering, "I would rather have you (his constituents) complaining to me that I voted wrong on nominating somebody than saying I'm not doing my job," according to a report in the Garden City Telegram

One conservative group said it would launch an ad campaign targeting Moran, while the other threatened to support a challenger from the right against the first-term senator in the Republican primary later this year.

Most Senate Republicans say a nomination to replace Scalia should be made next year by whoever wins the White House this fall. Only two Republicans, Susan Collins of Maine and Mark Kirk of Illinois, both moderates, are calling for hearings.

On Tuesday, Kirk, one of the most vulnerable Republicans who is running for re-election, blasted the GOP leadership for refusing to act on the nomination.