(Bloomberg) —The Senate is expected to vote this week on a measure to punish Russia with sanctions for interfering in the 2016 presidential election, and President Donald Trump would be “betraying democracy” if he vetoes it, Senator Lindsey Graham said.

Graham, Republican of South Carolina, said on CBS’s “Face the Nation’’ on Sunday that Russia must face retribution for hacking into Democratic Party emails and other actions — from providing arms to the Taliban to kill U.S. soldiers, to colluding to allow Syrian President Bashar al-Assad to keep chemical weapons and being complicit as those munitions were used against children.

Trump and all members of Congress should want to punish Russia for what they’ve done, and if the president rejects the bill his veto will be overridden, Graham said. “If the president doesn’t sign this bill to punish Russia, he would be betraying democracy.”

“Mr. President, the Russians did this,’’ Graham said. “You’re the commander-in-chief. You need to stand up to Russia. We’re never going to reset our relationship with Russia until we punish them for trying to destroy democracy, and that starts with more sanctions.’’

Floor Debate

Russia’s election meddling will be the focus of a Senate floor debate starting Monday, attached to a bill that would impose new sanctions against Iran for its ballistic-missile testing, support of terrorism and human-rights violations. Bipartisan negotiations could produce an amendment to impose new sanctions against Russia as well.

Republican Senator Bob Corker of Tennessee, chairman of the Senate Foreign Relations Committee, and Senator Ben Cardin of Maryland, the panel’s top Democrat, voiced optimism for an agreement to vote on Russia sanctions.

“We will have a Russia amendment, period,’’ Corker told reporters on June 8. The question is whether senators are able to meld different Russia sanctions proposals into one amendment. If not, there is still “an expectation there will be an opportunity to offer one or more amendments concerning Russia,’’ Cardin said.

The timing of consideration of the sanctions bill in the House is unclear.

While the Trump administration has called for tougher action against Iran, the president talked during the campaign of making deals with Russian President Vladimir Putin and easing the sanctions that President Barack Obama imposed over Russia’s annexation of Crimea and intervention in Ukriane.

But that prospect has become politically sensitive given the FBI’s investigation of Russia’s meddling in last year’s campaign and whether anyone close to Trump colluded in it.

Michael Flynn was fired as Trump’s national security adviser for failing to disclose to Vice President Mike Pence that he’d talked with Russia’s ambassador to the U.S. about the prospect of easing some sanctions.

Graham said on CBS he thinks Trump believes that pursuing Russia for interfering in the election suggests that he didn’t win fairly.

“I see no evidence of the president’s campaign colluding with the Russians,’’ Graham said. “I see all kind of evidence of the Russians trying to destroy our election and destroy democracy.’’