The Denver Post published a letter to the editor suggesting President Donald Trump should be executed for treason.

The letter criticized the president and Sen. Cory Gardner (R., Colo.) following Trump's summit with Vladimir Putin in Helsinki, Finland, and said Soviet spies Julius and Ethel Rosenberg, who passed atomic bomb secrets to Moscow, were executed for "far less."

The letter, written by Suzanne Gagnon of Lakewood, was in response to the paper's editorial last week, which gave tepid praise of Gardner. The editorial argued the Republican senator "deserves credit" for taking a tough stance against Russia and sponsoring legislation to add Russia to the state sponsor of terror list.

"Sen. Cory Gardner is insipid, at best," Gagnon wrote in her letter to the editor published Saturday. "His words are always carefully chosen and, if challenged, their intent open to ‘spinning' to his own advantage. No surprise here he didn't call President Donald Trump out by name.

"The legislation he has proposed is weak, not tough; it's simply more wordsmithing," she said. "Gardner is certainly not the only politician I take issue with, but I don't see the Denver Post championing anyone else like you champion Gardner."

Gagnon then compared Trump to the Rosenbergs, who were tried and put to death for espionage in 1953. She said there are "many more actions" that should be taken against Trump.

"If it walks like a traitor, and talks like a traitor, and acts like a traitor … it is a traitor," Gagnon said. "Ethel and Julius Rosenberg were executed on a basis of far less evidence than is had on Trump and many in his administration."

"Besides being in agreement with the actions recommended in the editorial of July 19, I believe there are many more actions that can and should be taken against Trump to keep him from destroying the U.S.," she said. "If our leader doesn't support any swift, significant pushback against Russian meddling, our votes aren't worth much."

Compass Colorado, a conservative nonprofit organization, said the editorial is in line with the "increasingly violent tone" of political rhetoric on the left.

"The mere fact the Denver Post would publish a letter to the editor with this type of language speaks to both the increasingly violent tone of liberals in Colorado politics and the desperation of the Post for readership," said Kelly Maher, executive director of Compass Colorado.

"This trend of violent language in Colorado is deeply concerning," she said. "Just a few months ago the Boulder Daily Camera published a letter to the editor asking if citizens have a moral responsibility to take arms against oil and gas well workers, and the liberal group ProgressNow Colorado tweeted out a picture of Senator Cory Gardner with blood on his hands after a shooting, and now this Denver Post letter."

"This violent and divisive rhetoric will do nothing to change hearts or minds, it's designed to entrench and inflame," Maher said.

The Denver Post pushed back on the idea that the editorial was extreme.

"We would never run a letter suggesting that the president of the United States be executed," said Megan Schrader, editor of the editorial pages. "Upon reviewing this letter, I don't think that was the letter writer's intent."

"She wrote to be critical of an editorial I wrote lauding Sen. Cory Gardner's efforts to impose sanctions on Russia and supportive of another editorial we had run that suggested actions Congress could take to respond to the Helsinki press conference," Schrader added.

Update 7:42 p.m.: This post has been updated with comment from the Denver Post.