WASHINGTON — Republicans in the House of Representatives are expected to rally Wednesday around a business tax break that would cost the government an estimated $155.5 billion over 10 years.

They’d do it without offsetting spending cuts or tax increases – deficit spending that most lawmakers and the insurgent tea party have long decried. And protests about overspending have helped stall Democrat-backed emergency programs such as extended unemployment benefits.

This latest battle over tax breaks – notably the research-and-development tax credit scheduled for a House vote Wednesday – is a vivid example of the clash between very different political philosophies, as well as a strategy of political amnesia when the situation demands it.

Democrats have long contended that emergencies need not be paid for. For months, they’ve pushed for an extension of emergency jobless benefits, which expired Dec. 28. Republicans tried to block it, arguing not only that such benefits often discourage people from looking for work, but also that the cost would add to the federal deficit.

In April, the Senate ended a months-long impasse and passed legislation to extend unemployment insurance for the long-term jobless through the end of May. Five Republicans joined Senate Democrats on a plan with a series of offsets, including a change in companies’ pension payments. The House hasn’t acted on the bill.

Republicans defend tax cuts by saying people will have more to spend, businesses will have new incentives to invest and hire, government will shrink and the economy will boom. The House plan not only makes the tax break permanent, but it also raises the tax credit rate from 14 percent to 20 percent, all without accounting for the billions in revenue the government would lose.

“It is allowing businesses who invest to keep more of that investment, to plow it back into research,” said House Majority Leader Eric Cantor, R-Va. Added Rep. Kevin Brady, R-Texas, one of the bill’s chief sponsors: “I’m tired of losing ground to America’s global competitors.”

Democrats cried hypocrisy.

“All of the wringing of hands and gnashing of teeth with reference to the deficit seems to go by the boards when the Republicans talk of tax cuts,” complained House Minority Whip Steny Hoyer, D-Md.

They also contend that many economists say unemployment insurance benefits are spent quickly and help promote growth.

The White House said Tuesday that if the bill reached President Obama’s desk, which is highly unlikely, he’d veto it.

“The administration wants to work with Congress to make progress on measures that strengthen the economy and help middle-class families, including pro-growth business tax reform,” an administration statement said. “However, making traditional tax extenders permanent without offsets represents the wrong approach.”

The House is expected to vote Wednesday on making the research and development measure permanent. Begun in 1981 and extended 15 times, it has broad bipartisan support and is considered an important incentive for business.