CAPITOL HILL: Tensions within the GOP over the mandatory budget caps set by the Budget Control Act burst into the open today. The chairman of the House Appropriations defense subcommittee repeatedly warned colleagues and the leaders of the Air Force this morning that they had no choice and must live within the Budget Control Act’s spending limits.

Then, this afternoon, Rep. Mac Thornberry, the chairman of the House Armed Services Committee — and 30 of his fellow Republicans — wrote a 13-page letter to the House Budget committee chairman urging him to bust the budget caps in the interest of national security.

Rep. Rodney Frelinghuysen, HAC-D chairman, warned Air Force Secretary Deborah Lee James and Chief of Staff Gen. Mark Welsh quite sternly that: “We do have to cut $10 billion [from the Air Force budget request] with you, or we will cut $10 billion without you.” He’d said almost the same words to Navy Secretary Ray Mabus and Chief of Naval Operations Adm. Jonatan Greenert the day before. Those cuts, he reminded the Pentagon leaders and his members, would be required to comply with Budget Control Act, which is the law of the land, he noted.

Rep. Rodney Frelinghuysen

Of course, one of the wonderful things about Congress is that it can write laws to get around existing laws. That was clearly what the 31 GOP members of the House Armed Services Committee on Thornberry’s side were trying to encourage Rep. Tom Price, chairman of the House Budget Committee, to consider starting when he sets the budget limits to which each major committee in the House must mark its bill.

Thornberry and his colleagues urged Price to set the committee’s mark at “the pre-sequestration BCA caps of $577.0 billion for national defense and $50.9 billion in the Overseas Contingency Operations account. If this is not feasible in the first year, the committee recommends, at a minimum, last year’s House-passed Budget Resolution level of $566.0 billion for national defense in the base budget for FY16 with restoration to pre-sequestration level funding in FY17 and out.”

Price and his Senate counterpart, Sen. Mike Enzi, are expected to produce the 2016 budget resolution by mid-to late April.

The Obama administration wants $561 billion for defense, which is $31 billion over the BCA caps. Thornberry and his colleagues are asking Price to approve $16 billion more than the Obama request.

The letter includes this pungent line, one sure to catch the eye of any Republican — except those who fancy themselves adherents of the Tea Party:

“It may seem ironic, but is still true, that reducing our military spending in the hopes of improving our financial situation may well bring about more instability in the world – economic and otherwise – that damages our economy and undermines the American way of life.”

Rep. Randy Forbes

Not all of the committee’s senior Republicans signed the letter. A marked absence was Rep. Randy Forbes, chairman of the seapower and power projection subcommittee. Forbes told my colleague Sydney Freedberg he refused to sign the letter because the amounts Thornberry and co. requested were not high enough. “[When you say] ‘we wouldn’t do anything less than the president’s budget,’ by implication you’re saying you’ll accept the president’s budget,” Forbes said. “I reject that approach…. I think we have an obligation, at least some of us, to be a voice to say that’s not good enough.”

“We have had a series of roundtable discussions with service chiefs [recently],” Forbes said. New Marine Corps commandant Gen. Joseph Dunford said, and Army Chief of Staff Ray Odierno agreed, that even the president’s request was not at the level they’d really need to meet new threats. “The commandant said if we go with the president’s numbers on the budget… the best I can do is to reset our military back to where it was over a decade ago. It would not even start to reconstitute us to where we need be for tomorrow,” Forbes recounted.

That’s why Forbes won’t sign Thornberry’s letter asking for the level of spending in the president’s budget, he said: “I reject that approach too, because I’m not content to build the armies of yesterday, I’m dedicated to building the armies of tomorrow,” Forbes said. “The men and women [of our military] deserve no more… our country can afford no less… as a party and a congress we should settle for no less…. which is going to be a dollar figure that is higher, Sydney, than even the president’s budget.”