Lawmakers are continuing to work on multiple defense bills this month, though they said yesterday some of them may not be resolved until September at the earliest.

Of the four Pentagon budget bills between the House and Senate–the authorization and appropriations measures in each chamber–only the House version of the policy-setting authorization legislation has been approved. The bills all guide Pentagon spending and activities for fiscal year 2013, which starts Oct. 1.

The Senate Appropriations Defense subcommittee (SAC-D) will mark up its version of the budget-setting defense appropriations bill “in about a week,” Chairman Daniel Inouye (D-Hawaii) said in a brief interview yesterday at the Capitol.

The SAC-D will be the last of the four major defense panels in Congress to unveil its version of the defense budget. After the full SAC, also chaired by Inouye, then passes the defense subcommittee’s bill, there will be little time for Senate floor action this fiscal year. Congress will break for August recess in less than four weeks, and then be in session just three weeks in September before FY ’13 starts. The Pentagon could be funded with a continuing resolution, which would temporarily maintain funding at FY ’12 levels, if the House and Senate have not come up with one appropriations bill that President Barack Obama signs before Oct. 1.

The full House is expected to debate its version of the defense appropriations bill next week, congressional aides said. The House OK’d on June 29 a so-called open rule for the budget-setting legislation that allows members to offer any amendments they want on the House floor. The House Appropriations Committee (HAC) approved on May 17 the bill up for debate, which exceeds spending limits dictated by the Budget Control Act of 2011 and is $8 billion larger than what the SAC-D is expected to propose.

The HAC bill makes similar proposals regarding weapon systems to those in the versions of the policy-setting defense authorization bill approved in recent months by the House and the Senate Armed Services Committee (SASC).

Those proposals, in the three bills, include adding funding for the Navy to buy a second Virginia-class submarine in FY ’14, blocking the Pentagon’s plan to allow a temporary shutdown in production of the M1 Abrams tank, prohibiting the administration from spending funding on the Medium Extended Air Defense System, and thwarting proposed reductions in Air National Guard and Air Force Reserve aircraft.

The policy-setting authorization bill is further along in the congressional approval process than the budget-dictating appropriations legislation is, though it remains unclear when the Senate will debate the authorization measure.

SASC Chairman Carl Levin (D-Mich.) told reporters yesterday he still hopes the chamber will act this month on the bill his panel approved on May 24. SASC Ranking Member John McCain (R-Ariz.) said Senate Majority Leader Harry Reid (D-Nev.) has not made it clear when he will bring the authorization bill to the floor for debate before the Senate’s month-long recess starts Aug. 3.

“That is a question I have been asking Sen. Reid continuously,” McCain told reporters at the Capitol. “We’re hoping that it can be brought up before” August.

The House passed its version of the authorization bill on May 15, calling for adding $4 billion in spending to Obama’s proposed Pentagon budget. The SASC’s version proposes a smaller boost of $498 million to the Pentagon plan.

The White House’s Office of Management and Budget (OMB) has said Obama could veto both the House-passed authorization measure and HAC-approved appropriations plan, saying they add too much funding to the Pentagon’s funding request and make unacceptable program changes.