"I have come to a stark and real conclusion about money that we have wasted and continue to waste in this effort: we are building infrastructure in Afghanistan that we cannot secure and that will not be sustained,” said McCaskill, who serves on the Senate Armed Services Committee.

“I can’t stand by as we spend billions on roads, electrical grids, bridges in Afghanistan, knowing the incredible need we have in this country for exactly that kind of investment," she continued. 

The amendment would target funds in the  Commanders’ Emergency Response Program and the recently created Afghanistan Infrastructure Fund, and would prevent resources from being spent on projects that cost more then $50,000.

McCaskill is currently engaged in a uphill battle to maintain her seat as a Democrat in a state that narrowly voted against Obama in the 2008 presidential election.