WASHINGTON — The House on Thursday headed toward passage of a $585 billion defense policy bill that gives President Barack Obama the authority to expand U.S. military operations against Islamic extremists in Iraq and Syria.

The sweeping legislation authorizes spending for the nation’s defense, from construction of ships, planes and war-fighting equipment to a 1 percent pay raise for the troops, while maintaining the prohibition on transferring terror suspects from the federal prison at Guantanamo Bay, Cuba, to the United States.

The bipartisan legislation traditionally garners strong support, but several lawmakers complained that they were barred from a fresh vote on authorizing military force. In an effort to expedite the bill in the lame-duck session, leadership allowed no amendments.

“These wars deserve a debate,” said Rep. Jim McGovern, D-Mass. “We’re getting more deeply involved in the war in Iraq and Syria.”

If passed as expected, the measure heads to the Senate, where Republicans are divided over the inclusion of unrelated provisions expanding wilderness areas in the West. Proponents of the bill hope to finish the bill next week and send it to Obama for his signature.

This year, work on the bill has added poignancy as the chairmen of the Armed Services committees in the Senate and House are retiring. Democrat Carl Levin is leaving after representing Michigan for 36 years in the Senate; California Republican Howard “Buck” McKeon is stepping down after a 22-year career in the House.
The bill is named for both men. The overall legislation endorses Obama’s latest request to Congress in the 4-month-old war against Islamic State militants who brutally rule large sections of Iraq and Syria. Obama sought billions for the stepped-up operation and the dispatch of up to 1,500 more American troops; the bill provides $5 billion.

The administration also pressed for reauthorization of its plan to train and equip moderate Syrian rebels battling the forces of President Bashar Assad. The bill would provide the core funding of $521.3 billion for the military and $63.7 billion for overseas operations in Afghanistan and Iraq, where fighting has lasted more than a decade. The bill would prohibit the retirement of the A-10 Warthog, the close-air support plane often described as ugly but invaluable.

The Pentagon sought cuts in military benefits. Lawmakers compromised by agreeing to make service members pay $3 more for co-pays on prescription drugs and trimming the growth of the off-base housing allowance by 1 percent instead of the Pentagon’s deeper 5 percent recommendation.

The legislation would change the military justice system to deal with sexual assault cases, including scrapping the nearly century-old practice of using a “good soldier defense” to raise doubts that a crime has been committed.

The bill includes a bipartisan plan crafted by three female senators that would impose a half-dozen changes to combat the pervasive problem of rape and sexual offenses that Pentagon leaders have likened to a cancer within the ranks.

The measure would give accusers a greater say in whether their cases are litigated in the military or civilian system and would establish a confidential process to allow victims to challenge their separation or discharge from the military.