Republican and Democratic negotiators are expected to agree to a budget deal this week setting spending levels for 2014. The Washington Post says that the deal will amount to “little more than a cease-fire.”

However, the deal being described in media reports would be much worse than a cease-fire for Republicans, at least for fiscally conservative Republicans. That’s because the Budget Control Act of 2011 and related sequester have started bearing fruit and are currently providing substantial discretionary spending control. Yet Republican leaders are apparently planning to throw it away in return for revenue increases and paltry spending trims.

In theory, Republicans have the upper hand in budget talks because current law specifies that discretionary spending will be modestly reduced in 2014 to $967 billion. Republicans always claim that they are for spending restraint, and here they just need to hold firm on current-law budget caps to save serious money over time.

However, the Post story indicates that the GOP may agree to scrap the budget cap for 2014 and spend up to $1.015 billion in return for a tiny cut to federal pensions and a revenue increase, possibly from auctioning radio spectrum.

That would be a giant cave-in because a precedent will have been set. The next decade of savings from current-law budget caps would be in jeopardy. If Republican leaders up-end the budget caps this year, they will empower big-spending Democrats, liberal Republicans, and appropriators to completely blow up the caps in later years.

A $48 billion cap overrun this year could set the stage for spending hundreds of billions of dollars more over the coming decade. That would be snatching defeat from the jaws of 2011’s modest budget victory.