The detainee language in the bill seems certain to generate the most heated debate, and House Armed Services Committee Chairman Buck McKeon (R-Calif.) spent considerable time Wednesday defending the language in the bill. McKeon said Congress was right to reaffirm the ability of the President to permanently detain terrorist suspects in last year's NDAA bill.

"In 2012, we affirmed that the President is authorized to detain certain al Qaeda terrorists pursuant to the 2001 authorization for use of military force," he said on the House floor. "Ten years after the horrific attacks of 9/11, it was time for Congress to once again ensure that our men and women in uniform have the authority they need to continue to fight and win the war on terror."

Last year's NDAA authorized the President to detain suspects, and included language that explicitly said U.S. citizens were not affected by the bill. Nonetheless, opponents said the detention of U.S. citizens could still occur, which prompted McKeon to add language in this year's bill, H.R. 4310, saying all terrorism suspects would be given full habeas corpus rights.

Despite this attempt to defuse the issue, Republicans and Democrats are expected to offer language removing this provision altogether. Armed Services Committee ranking member Adam SmithAdam SmithTrump’s defense spending boom that wasn’t No, Mr. President, you don't have the 'better ideas' on trade GOP chairman's Pentagon acquisition bill looks past ‘bright shiny objects’ MORE (D-Wash.) reiterated that he would offer an amendment to ban permanent detention.

"I do not believe the Executive Branch should have that power, to indefinitely detain or place in military custody people captured or arrested here in the U.S.," he said Wednesday night. Smith's amendment is supported by Reps. Justin AmashJustin AmashGOP lawmaker backs Dem push for Trump tax returns The Hill's 12:30 Report The Memo: GOP talk of impeachment highlights Trump’s troubles MORE (R-Mich.) and John GaramendiJohn GaramendiLawmakers urge debate on Afghanistan war Lawmakers sound alarm on space security North Korean tests augment calls for boosting missile defense systems MORE (D-Calif.).

Elsewhere, the bill includes language that would bar same-sex marriage ceremonies on military installations that Rep. Susan Davis (D-Calif.) said she opposes.

"We already had this debate. The American people support gays and lesbians openly serving in our military," Davis said. "Denying a service member the ability to use a military facility to hold a ceremony that other members have access to is wrong, and it's discriminatory."

Rep. Dennis Kucinich (D-Ohio) indicated that another issue that members could protest is Section 1221 of the bill, which he said "makes military action in Iran a U.S. policy." That language says it is U.S. policy to "take all necessary measures, including military action if required, to prevent Iran from threatening the United States, it allies, or Iran's neighbors with a nuclear weapon."

Kucinich said that later language in the bill calls for military deployment and the pre-positioning of aircraft, bombs and other materiel in preparation for a war with Iran.

Democrats in particular are also likely to argue that the bill authorizes $8 billion more in spending than allowed under last year's Budget Control Act (BCA). Smith raised this issue as a red flag Wednesday night.

"It is over what the Senate is going to mark up," he said of the bill, which authorizes $643 billion for the Defense Department and overseas operations. "We at some point are going to have to rationalize that, and figure out how to make our national security strategy and our defense budget work in an era when our budgets are coming down."

McKeon reiterated the GOP position that the House will approve appropriations bills that, all together, will stay within the BCA caps, because the $8 billion increase in defense spending will be offset elsewhere.

— This story was updated at 12:33 p.m. to remove Rep. Jeff Landry's name from the list of members who support the Smith amendment on detainees.