The Washington Post’s Chris Cillizza looks at what Republicans want to get out of the fiscal cliff negotiations — and where they might need to bend. (The Washington Post)

President Obama on Tuesday rejected a GOP proposal to collect new taxes from high earners by limiting their deductions and tax breaks, insisting that any deal to avert the year-end “fiscal cliff” must include an agreement to raise the top income tax rates.

“We’re going to have to see the rates on the top 2 percent go up. And we’re not going to be able to get a deal without it,” Obama told Bloomberg Television in his first television interview since the Nov. 6 election.

Senior Republican aides said the White House offered no additional response to the plan, maintaining a stony silence.

Obama instead appeared to toughen his stance on tax rates, the central dispute between the two parties. The top tax rate is set to rise automatically from 35 percent to 39.6 percent when the George W. Bush-era tax cuts expire in January.

In a news conference last month, Obama suggested that he might let the top rate rise to a level somewhat lower than 39.6 percent to satisfy Republicans who argue that higher rates would hurt small businesses. But on Tuesday, he seemed to block even that path to compromise, sketching out a two-step process that assumes full expiration of the Bush tax cuts in January followed by legislation that could lower the rate sometime next year.

‘Fiscal cliff’ calculator’: What it will mean for me

“Let’s let tax rates on the upper-income folks go up,” Obama said. “. . . And then let’s set up a process with a time certain, at the end of 2013 or the fall of 2013, where we work on tax reform, we look at what loopholes and deductions both Democrats and Republicans are willing to close. And it’s possible that we may be able to lower rates . . . at that point.”

Senior Republicans said they were astonished by the White House reaction to their proposal, which represented their first explicit offer to raise revenue. While the concession came after nearly three decades of strict GOP anti-tax orthodoxy, Democrats dismissed it as too little, too late.

Some conservatives, meanwhile, balked at the proposal drafted by House Speaker John A. Boehner (R-Ohio) and other senior House leaders. Sen. Jim DeMint (R-S.C.) said that “Boehner’s . . . tax hike will destroy American jobs and allow politicians in Washington to spend even more” without reducing the deficit. The Heritage Foundation said Boehner had “abandoned core conservative principles.”

But those voices were relatively few. Many other conservatives, including a number of Republican freshmen who have repeatedly frustrated Boehner’s efforts to negotiate with Democrats, said they were withholding judgment on the plan.

“I haven’t read the speaker’s proposal. You wouldn’t want me to have an opinion before I’ve read it, would you?” said Rep. Trey Gowdy (R-S.C.), one of the House’s most reliably conservative voices. “I try to be muted in my criticism of those who are willing to try to lead, particularly when I don’t have all the details.”

Rep. James Lankford ­(R-Okla.), another vocal conservative, said, “I’ve got to be able to see what it is.” For now, he said, “I’m comfortable with the speaker doing the negotiations.”

Their wait-and-see attitude comes as Boehner sent a message to his rank-and-file this week that stepping out of line will have consequences, yanking plum committee assignments from four conservative lawmakers who have repeatedly voted against House leaders.

But it also reflects an understanding that Democrats have pushed Republicans into an uncomfortable corner on the tax issue. Taxes will rise automatically on nearly 90 percent of taxpayers next year unless Congress acts. Obama is demanding legislation that would protect 98 percent of taxpayers while allowing rates to rise on the top 2 percent. If Republicans refuse, polls suggest they will take the blame for sending the nation over the fiscal cliff and raising nearly everyone’s taxes.

“I’ve said this for weeks now — the president does not fear the fiscal cliff,” said Rep. Steve King (R-Iowa). “That means he can push and push.”

Ed O’Keefe contributed to this report.