US lawmakers will vote today on whether to end American involvement in Yemen’s bloody civil war, an extraordinary effort to overrule presidential military authorisation just as Saudi Arabia’s crown prince visits Washington.

The rare Senate vote addressing American war powers aims to shut down US military involvement in Yemen within a month unless Congress formally authorises continued involvement.

The US military is currently supporting a Saudi-led coalition fighting Iranian-backed rebels in Yemen.

The vote, which was being forced to the floor by a bipartisan group of senators including Bernie Sanders, could cause diplomatic embarrassment on a day President Donald Trump when meets with Saudi Crown Prince Mohammed bin Salman, who is launching a three-week US tour.

Some US lawmakers have long expressed concern about the Yemen conflict, which has seen high levels of civilian casualties and caused a humanitarian crisis.

The Pentagon since 2015 has provided “non-combat support” to Saudi Arabia, including intelligence sharing and air-to-air refuelling for its war planes.

US Defence Secretary Jim Mattis last week asked Congress not to interfere with America’s role, warning that restrictions could “increase civilian casualties, jeopardise cooperation with our partners on counterterrorism, and reduce our influence with the Saudis – all of which would further exacerbate the situation and humanitarian crisis”.

More than 9,200 people have been killed and tens of thousands wounded in Yemen’s three-year-old war, which is seen as both a civil conflict and a proxy war between regional titans Saudi Arabia and Iran.

Senators Sanders, Mike Lee and Chris Murphy said earlier this month that their resolution would force the first-ever vote in the Senate “to withdraw US armed forces from an unauthorised war”.

“We believe that, as Congress has not declared war or authorised military force in this conflict, the United States involvement in Yemen is unconstitutional and unauthorised, and US military support of the Saudi coalition must end,” said Sanders.

Trump’s top military and diplomatic advisers said last October that the administration was not seeking new authority for conducting military operations in the world’s hot spots.

Congress first passed an authorisation to use military force, or AUMF, on September 14, 2001 – three days after the devastating attacks on New York and Washington by al-Qaeda hijackers.

Since then, presidents George W. Bush, Barack Obama and now Trump have relied on the order’s authority, along with a subsequent AUMF in 2002, as the basis for operations against armed Islamist groups.

Several Democrats, and some Republicans, have warned that the 15-year-old authorities are licences for endless US military engagement. – AFP, March 20, 2018.