Former Defense Secretary Robert Gates asserted Sunday it was a mistake that President Donald Trump didn’t act tougher with Russian leader Vladimir Putin after it was revealed that Russia tried to interfere in the 2016 election.

CBS host Margaret Brennan started the discussion by asking if it was “legitimate criticism” to accuse the president of not adequately confronting the Russian leader about the election meddling that the Mueller report asserts took place. (RELATED: Flashback: Robert Gates Said He Felt Pressured To Tell Obama He Would Be Loyal)

“I think that was a mistake, yes. I think he should have said, ‘we’ve had this discussion. The evidence is in. And don’t ever do this again, or there will be consequences for Russia.’ I think he very much should have raised it with him,” Gates responded during a Sunday interview on “Face The Nation.”

Despite the mistake, Gates made sure to mention the fact that Russia is suffering from greater sanctions under the Trump administration than under former President Barack Obama.

“I think in terms of the magnitude of the sanctions that have been put on Russia, they are more significant than have been imposed in the past,” he continued.

Gates addressed the Mueller report and said that the part about Russian influence in the election should not be dismissed.

“The piece of the Mueller report about Russian interference is not case closed,” Gates responded. “And frankly, I think elected officials who depend on honest elections to get elected ought to place as a very high priority, measures to protect the American electoral system against interference by foreigners.”

Russian leadership vehemently denied any election interference when the Mueller report came out. “The Mueller probe was an attempt to threaten the current government and influence U.S. foreign policy without offering any specific evidence,” state-owned Russian television network Rossiya broadcasted in April.

The report stated that Russian leadership sought to influence the outcome of the 2016 presidential election, but that no Americans assisted in that goal.

Republican Sen. Cory Gardner called for greater sanctions on Russia after the report was released. “I will keep up the pressure on the Putin regime and pursue additional sanctions — they cannot go unpunished,” he said shortly after the report was released.