Sen. Rick Santorum is not a subtle man. Pennsylvania's junior senator has strong beliefs that he refuses to mute out of deference to people, institutions or conventional wisdom.

During the contentious debate in 2003 about the U.S. Supreme Court's decision to invalidate Texas' sodomy laws, Sen. Santorum famously suggested that the decriminalization of homosexual sex could lead to the legalization of a host of social ills from bigamy to bestiality.

One would think the scorn he engendered then would temper his enthusiasm for opining so recklessly on the next hot-button issue (an issue that, fortunately, was resolved in the Senate last night). But the Republican's comments last Thursday only reminded us of his flair for the inflammatory.

Responding to the Senate Democrats' charge that Republicans were breaking the rules by opposing filibusters to stop judicial nominations, Sen. Santorum took the opportunity to go nuclear by making a dubious historical comparison.

"The audacity of some members to stand up and say 'How dare you break this rule' -- it's the equivalent of Adolf Hitler in 1942 saying, 'I'm in Paris. How dare you invade me. How dare you bomb my city? It's mine.' This is no more the rule of the Senate than it was the rule of the Senate before not to filibuster," he said.

While most of his colleagues consider it a breach of manners to compare the loyal opposition to Nazis occupying Paris, it's par for the course for the Republicans' third-ranking senator, who tends to see the world in black hats and white hats.

Hours later, Mr. Santorum clarified that his Hitler remark was "meant to dramatize the principle of an argument, not to characterize" Senate Democrats. "My point was that it is preposterous for someone to trample a well-established principle," he said, "and then accuse his opponents of acting unlawfully when they try to re-establish that principle."

We don't expect Rick Santorum suddenly to adopt a tone of responsible moderation. But if there is one thing that U.S. politics can do without, it's this kind of rhetorical firebomb that some members of both parties like to launch at each other. Last night's bipartisan compromise in the Senate over judicial nominations, however, proved that the spirit of moderation is still alive.

Rhetoric such as Sen. Santorum's certainly makes headlines and helps a lawmaker get something off his chest. But poorly chosen words don't help the public understand the issue. Besides, it is not becoming to the senator. It does not elevate the office. And it ill-serves Pennsylvania.