President Trump has been flirting with the idea of lifting U.S. sanctions on Russia and U.S. Senator Claire McCaskill (D-Missouri) wants Congress to have a say in whether that can happen. She’s among a bipartisan group of Senators proposing to allow Congress 120 days to review conditions and to decide whether to block Trump from lifting penalties.

Sen. Claire McCaskill (D-Missouri)

“It requires the president to get congressional input before there’s any decision to lessen the sanctions currently imposed on Russia as a reaction to their unlawful aggression in the Ukraine and obviously their attempts to impact the results of our elections as it relates to the hacking and other activities that have been uncovered,” says McCaskill.

Trump’s friendly attitude toward Russia has put him at odds with members of both parties who think the U.S. should take a tougher approach against the country.

“We are very worried and we think it’s really important that there’s a check on the president as it relates to any sanction activity towards Russia,” says McCaskill. “It is very concerning that every time Russia comes up with President Trump he is defensive of them.”

Under The Russia Sanctions Review Act, Trump must also certify that Russia has withdrawn support for separatist fighters in Ukraine or stopped activities meant to weaken the country’s stability. Trump would not be able to lift sanctions while Congress is reviewing the proposal.

The legislation is also co-sponsored by Republican Senators, including Lindsay Graham of South Carolina, John McCain of Arizona and Marco Rubio of Florida and Democratic Senators Ben Cardin of Maryland and Sherrod Brown of Ohio.

McCaskill sits on the Senate Armed Services Committee and as the top-ranking Democrat on the Senate Homeland Security and Governmental Affairs Committee.