In early 1953, the newly inaugurated President Eisenhower nominated Charles E. (“Chip”) Bohlen as ambassador to the Soviet Union. The man was eminently qualified—fluent in Russian and widely recognized as one of his country’s foremost Soviet experts. But he had been at the momentous Yalta summit conference of the Big Three Allied leaders—Franklin Roosevelt, Winston Churchill and Josef Stalin—who carved up the European continent in ways that later proved controversial. Bohlen had been merely a young interpreter at Yalta, but it didn’t matter. He quickly became a marked man to right-wing senators who at the time were making considerable political hay with their crusade to root out communists and other presumed security risks from the government.

Wisconsin’s fiery Joseph McCarthy and New Hampshire’s Styles Bridges attacked Bohlen as being insufficiently anticommunist for such a post. It caused a stir, but Eisenhower’s popularity and Bohlen’s reputation seemed adequate to ensure the diplomat’s Senate confirmation. Then the brash Democratic senator from Nevada, Pat McCarran, threw a wrench into the proceedings. He accused the new secretary of state, John Foster Dulles, of concealing damaging FBI evidence against Bohlen. A whisper campaign followed, suggesting Bohlen was homosexual, in those days considered a point of blackmail vulnerability.

McCarran didn’t present any evidence that there were in fact any such allegations residing in secret FBI files. He was merely repeating what he had heard, he said. But, without any shred of authentication, McCarthy promptly called upon Bohlen to take a polygraph test to prove his “innocence.’”

In terms of his slashing temperament, McCarran of Nevada bears a striking resemblance to Nevada’s current senior senator, majority leader Harry Reid. Reid took a leaf from the McCarran playbook—and McCarthy’s, too—in suggesting that GOP presidential candidate Mitt Romney never paid taxes over a ten-year period. Like McCarran, he had no evidence. Like McCarran, he sought to place his prey on the defensive with an allegation that he couldn’t back up. Like McCarran, he didn’t care whether he could back it up because his ultimate aim was to leverage the allegation for maximum political effect.

On one level, Reid’s actions seem to fit into senatorial behavior patterns that emerged back in the infamous McCarthy era. But it is instructive to note that no one on the Democratic side of the aisle has stood up to defend Romney against Reid’s unsubstantiated allegation or take Reid to task for such an assault on the hallowed comity for which the body was once—long ago—famous. That blithe attitude on the part of Democrats stands in sharp contrast to the reaction of responsible senators back in the McCarthy time, most notably that highly conservative paragon of senatorial rectitude, Ohio Republican Robert A. Taft.

Taft became infuriated when McCarthy raised the ante by demanding that Dulles testify before Congress under oath on the contents of the FBI’s Bohlen file. Dulles’s “statement not under oath,” he thundered on the Senate floor, “is just as good as Mr. Dulles’ statement under oath as far as I am concerned.” He noted that even FBI director J. Edgar Hoover considered lie-detector tests to be an inexact and hence flawed tool for seeking truth.

But McCarthy and McCarran persisted in their attack, and so Taft suggested a compromise. He said two senators, one from each party, should be designated to inspect summaries of the files. Most senators, anxious to lance this particularly ugly political boil, quickly embraced the idea, and Taft and Alabama’s Democratic senator John Sparkman were dispatched upon the mission. They spent three hours on the task and then reported back to the Senate that there was nothing in the files of a derogatory nature. Within days, Bohlen was confirmed on a 74-13 vote.

Consider the vector upon which the Senate has traversed since the days of McCarthy and McCarran, whose behavior was quite similar to the more recent behavior of Harry Reid. Unlike Reid, McCarthy and McCarran found themselves chastised by a leading member of the Senate who considered their behavior to be out of line. And the Senate actually trusted two of its number to look at the classified contents and report back truthfully on the evidence. Once they pronounced their findings, that was the end of it. Does anyone think such a level of trust would prevail under similar circumstances today? Hardly. The political leverage from unsubstantiated allegations is just too rich.

Indeed, how did Robert Gibbs, a senior adviser to President Obama’s campaign, react when interrogated by CNN’s Candy Crowley about why his boss wouldn’t distance himself from Reid’s unsubstantiated allegation? He repeatedly refused to answer, taking the offensive instead by blaming the whole affair on Romney’s refusal to release his tax returns beyond a pro forma two years. He caustically suggested that Romney should “go to Kinkos” and photocopy his tax documents for distribution to reporters around the country. He even offered to supply the nickles.

But, whatever one thinks of Romney’s refusal to come clean on his taxes (mystification is a logical sentiment), that doesn’t justify Reid’s suggestion that he knows what’s in the GOP standard bearer’s returns and that what he knows is adverse to Romney’s image. Since he can’t produce any proof either that he actually knows or that the information indeed is negative, the old rules of senatorial courtesy should apply. Under those rules, you don’t attack a colleague’s character without the justification of proof.

But the old rules of senatorial courtesy are in progressive deterioration now. And Harry Reid not only doesn’t seem to care; he is himself contributing to the deterioration. At least when McCarthy and McCarran acted that way, other senators stood up to call them on it.

Robert W. Merry is editor of The National Interest and the author of books on American history and foreign policy. His most recent book is Where They Stand: The American Presidents in the Eyes of Voters and Historians (Simon & Schuster).

Image: Center for American Progress Action Fund