WASHINGTON — A senior US House Republican says the White House must explain its Islamic State conflict strategy before lawmakers can consider a measure to authorize it.

The White House earlier this month sent Congress a draft authorization for the use of military force (AUMF) for the ongoing Islamic State conflict. Among other things, it restricts what US military ground forces can do and limits the legal basis for the ongoing conflict to three years.

The House Armed Services Committee on Tuesday will hear from Pentagon policy chief Christine Wormuth and US Central Command chief Gen. Lloyd Austin about the draft AUMF. But before they discuss that measure, HASC Chairman Rep. Mac Thornberry, R-Texas, echoing a slew of Republican senators, wants specifics on the Obama administration strategy for defeating the violent Sunni group.

"Over the past year, the developments in CentCom have been troubling. The rise of [Islamic State], questions about the future security situation in Afghanistan, the government of Yemen's fall to Iranian backed rebels, and the prospect of a deal ratifying Iran as a threshold nuclear power all have created serious stress on our strategic position and on our alliances," Thornberry said in a version of his hearing opening statement released Monday evening.

"Any notion that the US could pivot away from the Mid East toward other regions has proven to be naïve at best," he said. "Part of the challenge here is the absence of a comprehensive strategy across the Middle East. The limited approach that the president has taken has left instability and weak, or failed, states from Libya to Yemen."

Thornberry wants to hear about "a comprehensive strategy, or at least the foundations of a strategy, which will help provide a roadmap toward a more stable Middle East led by responsible actors."

Crafting an AUMF that can pass both chambers will be tricky work.

That's because, as usual, the two parties are split on how it should be worded. Republicans believe the White House's draft would tie the hands of this and future commanders in chief; Democrats think it is too legally vague.

To the former point, Thornberry says his committee "needs to hear any operational concerns about various AUMF proposals that contain restrictions on how we engage the enemy."

He also believes US officials should be mindful not to do anything that would further bolster Iran's standing in the region.

"I believe that it is also critical that we do not validate Iran's standing in the region, either through working with them or allowing them to have threshold nuclear capability," Thornberry said. "That has and will breed instability and increase security competition in both the Middle East and the wider geopolitical order. This must not be allowed to happen."

Last week, Thornberry's HASC leadership counterpart, Ranking Member Rep. Adam Smith, D-Wash., expressed doubts about Congress' ability to pass what would be the country's first new war authorization measure in 13 years.

"Unfortunately, I am skeptical that Congress will find the will to overcome our internal divisions," Smith said last Thursday, "both between parties and internal to them, to authorize this action."