Republicans are pressing the Pentagon to share details about how so-called sequestration budget cuts of $500 billion, which could start next January, would impact the defense budget.

Senate Armed Services Committee (SASC) Ranking Member John McCain (R-Ariz.) offered an amendment yesterday to an agricultural bill calling for the defense secretary to report by Aug. 15 on the impact the decade-long sequestration cuts would have on the military in FY ’13, the first year that would be impacted. The language mirrors a provision in the fiscal year 2013 defense authorization bill the SASC approved May 24, and McCain pledged to keep offering the amendment to addition legislation to force the matter.

“Congress needs an official, detailed assessment from the (Defense) Department on the serious damage to military readiness and the increased risk to our military operations in Afghanistan which would result if sequestration is allowed to occur due to the inability of the (Obama) administration and Congress to enact an alternative deficit reduction plan,” McCain said yesterday in a statement. Defense Secretary Leon Panetta insists the Pentagon has not conducted contingency planning for the sequestration reductions, though he has said the White House’s Office of Management and Budget may direct it to do so this summer.

McCain’s comments came as Republican lawmakers and military advocates continued to sound alarms about the impact of the $500 billion in long-term defense sequestration cuts, which could start next January and come on top of a $487 billion reduction to the Pentagon’s 10-year spending plans that the military already is planning for.  The sequestration cuts, triggered by the failure of a congressional “Super Committee” to craft a deficit-cutting deal last year, total $1.2 trillion over nine years and also would impact non-defense spending.

Many congressional observers expect Congress to wait until after the November presidential election to seriously work on an alternate plan to sequestration.

“We cannot wait until after the election to act,” McCain said, citing concerns about defense firms cutting employees amid concerns about the looming sequestration cuts.

Republicans have offered anti-sequestration plans opposed by the Democrat-run Senate and the White House. Those include a bill that passed the GOP-controlled House that would thwart the first year of sequestration cuts by reducing entitlement programs. Republicans in the House and Senate also have offered plans for preventing the first year of the cuts by reducing the federal workforce.

The SASC is calling on the White House to work with lawmakers on a plan to prevent the defense sequestration cuts.

The committee’s report on its FY ’13 defense authorization bill, which it filed in the Senate this week, says it “urges the administration and Congress to work together, beginning immediately, to develop and introduce in both Houses of Congress not later than September 15, 2012, a proposal to replace the automatically triggered, across-the-board reductions in fiscal year 2013 funding required by sequestration, in order to avoid the devastating consequences of continued inaction.”

McCain and SASC member Lindsey Graham (R-S.C.) told reporters Tuesday they are ready to seriously negotiate with the administration a deficit-cutting plan that could replace the sequestration cuts. They said they are open to considering additional government revenues–such as closing tax “loopholes”–which Republicans often oppose.

“I think putting revenues on the table makes sense,” Graham said. “You don’t raise tax rates, you close loopholes and apply it to the nation’s problems. The nation’s problems are preserving our defense and getting out of debt.” He said Democrats have to be “equally bold” on reforming entitlement spending.

McCain told reporters: “We are willing to talk about everything” with the White House. He noted “revenue-raisers” the Super Committee considered last year.

The amendment McCain offered to the so-called Farm Bill, which the Senate is debating now, also is supported by all 11 SASC Republicans. The amendment, like the SASC bill, calls for the report from the Pentagon to contain an assessment of sequestration’s potential impact on the armed forces’ readiness and ongoing military operations. Such a report would include a list of “the programs, projects, and activities” across the Pentagon that would be curtailed or killed because of sequestration, along with an estimate of “the number and value of all contracts that will be terminated, restructured, or revised in scope as a result of sequestration, including an estimate of potential termination costs and of increased contract costs due to renegotiation and reinstatement of contracts,” the amendment says.

It says the report should include an assessment on sequestration’s potential impact on the Pentagon’s ability to carry out national military strategy, as well as any changes to chairman of the Joint Chiefs of Staff’s Risk Assessment that would be spurred by sequestration. The report, further, would include assessment of civilian job losses under sequestration, according to the amendment.

McCain also said yesterday lawmakers need to “fully understand” how the administration’s new position that war funding would be subject to sequestration cuts would impact ongoing military activities and troops. The Pentagon said last week that so-called Overseas Contingency Operations funding would be factored in to the reductions, even though Defense Secretary Leon Panetta said last year they would not.

Graham said Tuesday that news could spur some of his fellow lawmakers to fight more vehemently against sequestration and perhaps sway stances on not allowing new government revenues in a replacement deficit-cutting deal.

The Center for Security Policy held an event in Washington yesterday dubbed “Like Shooting Ourselves in the Head:” Potential Economic and National Security Implications of Sequestration. The national-security think tank released new data on job losses across the country that the sequestration cuts could spur.

At the event Mackenzie Eaglen, a fellow at the conservative American Enterprise Institute, noted how contractors are already anticipating sequestration cuts and withholding their own investments.

“That’s exactly what we’re seeing now, and that’s going to continue to snowball as November nears,” she said. “So this is not a problem to be solved in January, much to the contrary of conventional wisdom. This is something that starts now, and unfortunately I’m not sure that we see a solution on the horizon.”