Sen. Ben Sasse, R-Nebraska, says that President Trump "isn't leading" after a stunning performance in Helsinki, Finland on Monday where he neglected to rebuke Russia's interference in the 2016 election and stood by Russian President Vladimir Putin's claims that the Russian state did not meddle in the U.S. election process.

"Right now the president isn't leading, we negotiated from a position of weakness yesterday and Vladimir Putin walked away from Helsinki with a win, it's a disaster," Sasse told "CBS This Morning" on Tuesday, joining the growing chorus of Republican and Democratic lawmakers critical of Mr. Trump's comments on Monday.

Sasse says that too often, Americans are seeing a "Trump-first policy rather than America-first policy" play out, leaving many people "scratching their heads" and questioning why Mr. Trump is siding with a known adversary of the United States.

"There is no debate inside the U.S. intelligence community that Russia tried to disrupt and hack the American election in 2016, but in a way more fundamentally what they're doing today and planning to do in the future, is continue to sow the seeds of distrust and undermine American public confidence," Sasse said.

He added, "When you see that and you have a choice between siding with Vladimir Putin or siding with patriots in the U.S. intelligence community, there's no choice here, the answer is obvious and yet we didn't see that yesterday."

While the Republican agreed with the president's sentiments that it's "better to get along with your enemies and your competitors on the global stage than to get into a hot war with them," he said it's imperative that the American people "have a shared understanding about who we are and who Putin is."

"We shouldn't just let yesterday be swept under the rug, we have to explain American values and have to explain why they're in conflict with Putin's" Sasse said, suggesting that the U.S. should respond by ramping up further sanctions on the Russian government and Putin's "thugs."