WASHINGTON — On Monday, President Obama made his statement about how the government ought to change its spending habits: a gradual plan that minimizes immediate pain by phasing in cuts over a decade.

Starting today, House Republicans will move forward with a very different approach, one intended to be viewed as radical and painful. Their proposal deals not with theoretical deficit targets set far in the future but with the final seven months of this year’s budget, a period left in flux by congressional inaction.

House Republicans want to cut $61 billion from the budget, which would amount to the most significant government contraction since the end of World War II. Decried as “dire” and “disturbing” by Democrats, the plan has become a test for how far Republicans are willing to go in order to deliver on the promise of fiscal austerity that GOP candidates pledged last year to voters.

“It’s big, and it’s real and it can impact people’s lives,” House Majority Leader Eric Cantor, R-Va., said Monday of the House legislation. “But we have a budget deficit right now of nearly $1.5 trillion. We have a lot of work to do.”

This week’s House debate also marks the first effort by the new GOP leadership to live up to a vow to allow amendments to be offered from all ideological corners. The result could be spending cuts even larger than those outlined in the bill, which already tops 350 pages.

Senate Democrats will put forth their own spending plan, which is expected to be vastly different from the House version. But they’re not planning to consider it until the first week of March, days before a stopgap measure that has been funding the government expires.

That leaves very little time to resolve vast differences between the two chambers. If House and Senate leaders cannot reach a deal by March 4, the federal government would shut down until a deal is reached.

Some lawmakers have suggested another stopgap measure, perhaps lasting just a few weeks, could be approved while the two sides and the White House continue negotiating. Senate Democrats will discuss their spending strategy during a meeting today.

Although members of both parties said they are determined to avert a shutdown, leaders acknowledged that the House Republican proposal, in both its scope and specificity, appears to leave little negotiating room.

“They’ve dug themselves into something of a hole because they’ve cut so deeply,” said Sen. Charles Schumer of New York, a senior member of the Senate Democratic leadership. “I was surprised they went that quickly and that far.”

Schumer said Senate Democrats would counter the House GOP proposal with their own reductions. “The Democrats are universally for some reasonable cuts,” Schumer said. “The president has put together a pretty good blueprint,” singling out 200 specific programs for reduction and consolidation as part of a combined approach to deficit reduction that also includes tax increases.

Under the House GOP plan, global AIDS funding would dry up. Road construction contracts would be terminated. Police departments, schools and the Chesapeake Bay cleanup effort would see federal support plummet.

Secretary of State Hillary Rodham Clinton denounced the cuts in a letter to House Appropriations Chairman Harold Rogers, R-Ky., noting that the legislation would reduce humanitarian assistance by 41 percent for the rest of the year. Clinton delivered the same message Monday at a private lunch with House Speaker John Boehner, R-Ohio, warning that her department would have to “scale back” diplomatic efforts in key countries such as Iraq, Afghanistan and Pakistan.

“The scope of the proposed House cuts is massive,” Clinton told reporters. “The truth is that cuts of that level will be detrimental to America’s national security.”

Homeland Security Chairman Peter King and freshman Rep. Michael Grimm, both Republicans representing the New York City area, urged in a letter to Boehner that the House reconsider proposed cuts to mass transit, Amtrak, local police forces and a heating assistance program for low-income households that Obama also proposed scaling back in his budget.