John Boehner says conservative groups criticizing the latest budget deal have “lost all credibility.”

Has the speaker of the House lost his mind?

Republicans have certainly cut worse deals with the Democrats than the controversial pact between Paul Ryan and Patty Murray. This one doesn’t increase marginal income tax rates, like the 1990 “read my lips” budget agreement between the Democrats and President George Bush. It doesn’t create the biggest new entitlement since Lyndon Johnson ushered in the Great Society, like Medicare Part D under Bush the Younger.

But sequestration marks the only time congressional Republicans have won a major spending battle against President Barack Obama. The Ryan-Murray deal essentially trades away the next two years of cuts.

Ryan insists that the deal “will provide $63 billion in sequester relief — split evenly between defense programs and other domestic priorities — in exchange for $85 billion in savings elsewhere in the budget.” That’s an extra $23 billion in deficit reduction.

But the savings come in the future. The voided spending cuts occur over the next two years. If Congress can vacate these previously enacted spending cuts, why can’t they roll back the future savings when the time comes?

It’s almost like passing amnesty for illegal immigrants now and waiting for border security later.

Maybe the Ryan-Murray deal will turn out as promised. But that would be much easier to believe if Beltway Republicans didn’t have a bigger credibility problem that outside conservative groups.

It wasn’t the Club for Growth that got elected in 2010 promising $100 billion in spending cuts, only to immediately shrink that figure to $58 billion upon taking office.

It wasn’t Heritage Action that had to be dragged kicking and screaming into upping the spending cuts slightly to $61 billion — and then shrinking it again, all the way back down to $38 billion.

Then it turned out that the actual deficit reduction for fiscal year 2011, the beginning of the tea party Republican House majority, was just $352 million. But that can’t be pinned on FreedomWorks.

Wait, you say. These spending disappointments were because House Republicans had to deal with Democrats, who still controlled the Senate and the White House this whole time.

But what about when Republicans controlled both Congress and the White House for most of the period from 2001 to 2006? During this period of time, No Child Left Behind, Medicare Part D, Sarbanes-Oxley, McCain-Feingold, the Patriot Act and bloated farm, transportation and energy bills all became law. Discretionary spending grew twice as fast as it did under Democratic President Bill Clinton.

Should we blame that on Paul Teller, the longtime conservative staffer recently sacked for not supporting the leadership’s spending machinations? Was that Matt Kibbe’s fault?

George W. Bush and Republican majorities added a Cabinet department rather than abolishing any, grew the Department of Education Ronald Reagan once pledged to close down. No Child Left Behind was Boehner’s baby as much as Bush’s.

Even if you exclude homeland security, domestic discretionary spending increased 40 percent from 2001 to 2006, a 7 percent annual growth rate, with mostly unified Republican control of the federal government. That compares to a 39 percent increase over Clinton’s entire two terms as president.

Congressional Republicans reined in Clinton’s spending for a good part of the 1990s. But by 1998, they started unveiling budget proposals that outspent Clinton’s. Spending on the liberal Goals 2000 education program doubled, even though Republicans had once promised to get rid of it entirely.

According to the Cato Institute, the combined budgets of the 101 largest federal programs Republicans had pledged to abolish in 1994 actually grew by 27 percent. That’s not a problem of tea party credibility. There was no tea party at the time.

None of this is to say that outside conservative groups have always been reasonable in their demands. The partial government shutdown — to which Boehner acquiesced — did more to weaken the GOP’s leverage in future spending fights than to defund Obamacare. Partisan infighting helped cost Republicans Senate seats that would have strengthened their current bargaining posture.

But lest we forget, these conservative pressure groups exist in the first place because government tends to get bigger and more expensive even after Republicans win elections. That isn’t exclusively because of broken Republican promises — the electorate hasn’t been clamoring for a return to constitutional government. Broken Republican promises haven’t helped, however.

Some self-described conservative groups are “misleading their followers,” winning power and raising millions of dollars in the process. Historically, the largest of them has been the Republican Party.

W. James Antle III is the editor of The Daily Caller News Foundation and author of the recently released book “Devouring Freedom: Can Big Government Ever Be Stopped?“ Follow him on Twitter.