Stephen Colbert does a crap Donald Trump impression but his political analysis isn't half bad. 

In a rude, crude, and mostly correct monologue about the failure to repeal and replace Obamacare, the "Late Show" comic absolutely savaged Republicans.  Honestly, the GOP had it coming. 

"When they knew Barack Obama would veto it, the GOP voted more than 60 times to repeal Obamacare," Colbert joked. " But now that they can actually do it, they don't have the balls.  All those times they voted, they must have just been yanking their own lever.  But now, when they have a Republican president, they can't get their vote up." 

Suddenly offended by locker room talk, social conservatives will complain about that onanism quip.  But that electorate deludes itself if they believe Colbert's bawdy humor is the real offense. 

The off-color jokes aren't important.  It's the content that matters.  And for an unabashedly liberal funnyman, Colbert understands perfectly what Republicans have been pulling over on their base for the better part of a decade. 

"Republicans said one thing for the last four elections," Colbert explained as increasingly awkward photos of old white Republicans flashed on screen. " It was your one job.  It's your tag line.  It's your motto.  It's Paul Ryan's tramp stamp." 

"And it wasn't just the House of Representatives and the Senate," Colbert continued, "it was also our 'Chucklehead in Chief' Donald Trump, who promised throughout his candidacy to repeal and replace Obamacare on Day 1." 

Of course, those zingers weren't especially clever.  But that's because they didn't need to be.  A student of politics and comedy, Colbert knows that there's always truth in kidding.  He knows that if he reads the headlines with a little color and a bit of context, Republican incompetence can generate the laughs. 

And then Colbert stuck the landing on his shtick without a joke but with brutal analysis. 

"All their promises are lies, and not just lies to the whole American public, specifically they lied to their voters and the people who trusted them," Colbert quipped.  He's not wrong. 

Philip Wegmann is a commentary writer for the Washington Examiner.