Lawmakers return to Capitol Hill on Tuesday with a list of critical defense bills to advance before their extended summer break begins July 15, even if none of them has a chance to become law before this fall.

Most of that work requires Senate action, with the annual defense appropriations bill awaiting floor debate this week and the annual defense authorization bill needing procedural approval from senators to move ahead to conference work.

In the next nine days of session (fewer if congressional leaders break early because of unbreakable deadlocks), lawmakers will also need to decide whether to advance key reforms for the Department of Veterans Affairs, including an omnibus bill that supporters had hoped would be approved before the Memorial Day break in May.

The work now is critical to give staffers from both chambers the ability to debate and refine the measures over the next two months, while lawmakers are back home preparing for the November elections.

Defense appropriations

First up is the fiscal 2017 defense budget measure, scheduled for procedural votes later this week in the Senate. The plan under consideration totals about $575 billion, roughly the same as the House plan passed four weeks ago, but contains radically different funding methods to get to that total.

The House plan includes almost $17 billion more base defense funding than Senate appropriators support, raiding temporary war funds for overseas operations to pay for what Republican lawmakers from the lower chamber call critical military needs.

But White House and Senate leaders have rejected that idea, noting it leaves troops in Afghanistan and the Middle East without guaranteed funding past April of next year.

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Finding a compromise between the two plans will require the two chambers to start conference negotiations on the appropriations bills, which requires the Senate to pass a draft to send to conference.

But lingering fights over congressional spending caps could scuttle even passing that initial draft of the measure, creating headaches for staffers and forcing lawmakers to more seriously consider continuing budget resolutions to fund the military past the end of the fiscal year instead of a stand-alone budget.

Defense authorization

The annual defense authorization bill pairs with the annual appropriations bill to complete Congress' military budget plans for next year, and has already been passed by both chambers.

Now leaders just need to find time to name conferees and let them start working on compromise language. The move is expected to be non-controversial, but lawmakers did not find time to do it before the July 4 break.

Both the House and Senate have included significant reforms in their authorization drafts, including an overhaul of the military medical system and new defense acquisition rules. Reconciling those issues alone will take weeks of behind-the-scenes work.

But the two chambers also need to work out a compromise on two different military pay plans — the House backs 2.1 percent starting in January, the Senate wants 1.6 percent — and a potential overhaul of housing allowance.

If they can find common ground, lawmakers could finalize the authorization bill in their short session between their summer break and their pre-election break, which starts in October. The legislation has been passed for 53 consecutive years, but typically final approval doesn't come until late in the year.

Veterans reforms

The House has already passed a series of bills providing new accountability rules for the Department of Veterans Affairs and expanding health care access for veterans, but Senate leaders have been hoping for a single omnibus bill to tackle those issues and a host of others.

That legislation — introduced by Senate Veterans Affairs Committee Chairman Johnny Isakson, R-Ga., in May — has been stalled for weeks. Isakson said he hopes to move the measure in the next two weeks, in the hopes of giving House staffers the opportunity to consider it over the August break.

Several lawmakers in the House have already reviewed and blasted the measure, calling its accountability provisions too light and its costs too unclear. But Isakson said he believes the bill is an important first step towards passing sweeping VA reform provisions sometime this fall.

A floor push by multiple members of the Senate committee late last month failed to jump start conversation on Isakson's measure.

If a chamber agreement can’t be reached, the legislation risks being relegated to the waning days of the lame-duck session late this year, when many lawmakers are reluctant to pursue such massive reforms.

Leo Shane III covers Congress, Veterans Affairs and the White House for Military Times. He can be reached at lshane@militarytimes.com.