WASHINGTON — Lead staff for the Senate and House armed services committees are readying for what is likely a summer-long conference process to reconcile differing defense policy bills, where the toughest issues are said to be funding, military health care reform and acquisition reforms.

Facing White House threats to veto both bills, Defense Secretary Ash Carter's charge that the bills represent "micromanagement" and closed-door negotiations with each other, the staff directors for the HASC and SASC offered defenses of their committee's approach to the 2017 National Defense Authorization Act (NDAA).

At an event hosted by the conservative think tank American Enterprise Institute on Tuesday, SASC Staff Director Chris Brose and HASC Staff Director Bob Simmons said both bills are seeking to help the military be more agile, innovative and robust.

"The objectives are the same, the intent is the same," Brose said.

Simmons defended the House-approved NDAA's plan to stick to the bipartisan budget deal but use $18 billion from the overseas contingency operations fund to pay for base budget items, expecting the incoming president will ask Congress for a supplemental defense spending package.

Simmons said the president's veto threat over the bill was "ironic," noting a Democratic Congress acted similarly in 2008, just before the Obama administration began.

"It's not like we haven't done this before, and in fact it was the Democrats who did it last time," Simmons said. "Then the candidate who ends up being the president can make their own assessment of what the foreign policy is, and the direction they want to take the country, then ask us for the funding appropriate for that effort."

Opponents have said the House NDAA takes funding from troops, but that is "wholly incorrect," Simmons said. The bill, he said, adds money to ready troops who are next to deploy.

"We're doing all these things to help the Department of Defense," Simmons said. "If [the president is] going to veto it, he's operating under false pretenses. We are taking care of the war fighter. We want to make sure those kids go into harm's way with what they need."

The Senate took a different tack on funding, meaning House and Senate conferees will have to work it out. Asked how the Senate might approach these talks, Brose said it was too soon to say as SASC Chairman John McCain, R-Ariz., and HASC Chairman Mac Thornberry, R-Texas, had yet to meet on the matter. Both chairmen have sought more troops and hardware left out of the president's 2017 budget request, he noted.

"We have no disagreement over the need for this, and the challenge is how you deliver it with a top-line both sides agree is inadequate," Brose said.

The Senate's NDAA blows up the position of AT&L undersecretary — currently held by Frank Kendall — and hands its duties to a new undersecretary of defense for research and engineering, or USD(R&E), and the renamed undersecretary of management and support, or USD(M&S). The USD(R&E)'s job would be to champion innovation for DoD.

The SASC's far-reaching reforms are aimed at untangling an acquisitions system that too rarely succeeds when "innovation is the sidecar" and "feels like a series of small-scale insurgencies," Brose said. It also continues last year's approach, which placed more acquisition authority in the hands of the services.

The House's NDAA's acquisition reform focus is to steer DoD away from lengthy, ambitious programs and toward incremental, rapidly fielded breakthrough technologies. It also aims to shake up the Pentagon's risk-averse culture, Simmons said.

"You don't have to solve the whole problem," Simmons said. "It's a question: If I give you 30 percent of the capability, and you can field it today, or would you rather wait 15 years to get a 100 percent solution? Well if 30 percent today gives you a better position on the battlefield, you want that today."

Twitter: @ReporterJoe