Democratic congressional leaders have called for an ethics investigation into Rep. Anthony Weiner (D-N.Y.), following revelations that he shared lewd content with women he met online and lied about it. Republican National Committee Chairman Reince Priebus said that’s not good enough and he wants Weiner to resign.

“Do we really need an ethics investigation to determine whether this guy is a creep or not? I mean, really?” Priebus told reporters this morning. “We need to investigate — use taxpayer dollars — to make a determination?”

Now, Priebus is the RNC chairman, so this is pretty much what he’s supposed to say. A Democrat gets caught up in an embarrassing scandal? Call for his resignation. It’s the obvious thing for a party chief to do.

Priebus’ problem, though, is that the more he pushes this, the more he gets asked that other question.

He declined to comment on previous Republican sex scandals, including one involving Senator David Vitter of Louisiana, who remained in office and was re-elected after he acknowledged in 2007 that he committed “a serious sin” in soliciting the services of a prostitute. Mr. Priebus said that he was not the party chairman at the time and had no authority to weigh in on the matter.

“Everyone wants to talk about David Vitter,” Mr. Priebus said. “I’m not going to re-litigate David Vitter. I think it’s wrong, too, but I’m not going to re-litigate David Vitter. We are in the moment now.”

What a clever little phrase. “We are in the moment now.” It has a vaguely metaphysical quality.

But that doesn’t make it persuasive. Priebus wants us to think Weiner is “a creep.” Given the last two weeks, that’s an argument that will likely resonate with a lot of folks. But there are lots of creeps in Congress, and the head of the Republican National Committee isn’t calling on all of them to resign.

In fact, one creep in particular is of interest. Weiner had explicit communications with women he met online, but he didn’t break any laws and didn’t even commit adultery. David Vitter, a right-wing family-values lawmaker, hired prostitutes more than once. In at least one instance, he communicated with a madam about hiring a hooker while he was on the floor of the House. We don’t know if Vitter used taxpayer resources for any of his trysts, or anything about the women he paid to have sex with him.

Which of these two men appear to have committed a more serious transgression? I’ll give you a hint: it’s the one Priebus doesn’t want to talk about.

“We are in the moment now”? Fine. David Vitter is in the Senate right now. If Anthony Weiner has disgraced himself so severely that he must give up his office, why should Vitter remain? Hell, even former RNC Chairman Michael Steele isn’t buying Priebus’ line.

For that matter, note that while Nancy Pelosi called for an investigation into the Weiner matter, Senate Minority Leader Mitch McConnell (R-Ky.) made no comparable call about Vitter.

So, what’s it going to be, Reince? Are we holding lawmakers to the highest of standards or aren’t we?

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.