"No longer can we ignore the wounds of war from toxic exposures," said Senator Jerry Moran of Kansas, who helped push the legislation.
"Needless to say he spent his final three years on earth battling the war that followed him home."
The president can simply choose to veto the resolution rescinding the mandate if it passes the House.
Senator Jon Tester said the proposed spending increase "strengthens our military" in the face of adversaries like China.
"There's no way that I would vote to prevent the minority from having input into the process in the Senate," Manchin said.
Some Democrats worry that Republicans will use the filibuster to stop President Joe Biden's progressive legislative goals.
"American troops have been in Afghanistan for nearly 18 years, Iraq since 2003 and in Syria since 2015," Senator Bernie Sanders said.
The GOP celebrated Wednesday what Senator Jon Tester called "one of the shittiest bills" ever.