CLEVELAND -- Gov. Chris Christie had a rough week.

Despite being the first 2016 Republican candidate to endorse Donald Trump for president and stoutly defending him after making comments about a federal judge that were what Speaker of the House Paul Ryan called "the textbook definition of racism," the governor was nonetheless passed over as Trump's running mate.

Since Trump made his formal announcement of a VP pick on Saturday, social and mainstream media have been abuzz with pundits offering both reaction and explanation.

Perhaps most succinct was the analysis of GOP strategist Mike Murphy, who's advised Republican governors like Gov. Christie Todd Whitman and Gov. Arnold Schwarzenegger, and most recently ran former Gov. Jeb Bush's 2016 super PAC, "Right to Rise."

Christie had been running Trump's transition planning efforts, and as the Washington Post's Robert Costa noted, and had been, perhaps, a little too helpful.

You know who helped Paul Manafort coordinate that Pence summit with Trump in April? Chris Christie — Robert Costa (@costareports) July 16, 2016

Compounding the insult, Pence had previously endorsed Trump's rival, U.S. Sen. Ted Cruz of Texas, over Trump.

Why did Christie fall short? It wasn't just that his resume lacked federal legislative experience, which Pence has plenty of after six terms in Congress.

To hear President Ronald Reagan's former campaign manager Ed Rollins explain it in the New York Times, part of it surely was Christie's Bridgegate scandal, the trial for which starts in September.

"I was going to say he could be secretary of transportation, but that probably wouldn't be a very good thing for him," Rollins said of Christie in the New York Times on Saturday. "Though he has some experience there, controlling bridges and planes and that sort of thing."

But there were other reasons, some of which couldn't be helped.

"VP's are always about ticket-balancing," said Stu Loeser, formerly chief spokesperson to New York City Mayor Michael R. Bloomberg, "and he doesn't counter-balance."

As Loeser noted in an interview with NJ Advance Media, "Chris Christie would be a fantastic attack dog, but that's not an area of weakness for Trump."

More, because of his northeastern pedigree and right-of-center governance record, "he does nothing to shore up the party base who are nervous and might not turn out... If you drive a Camaro, you don't wake up and say, 'Gee, I also need a Mustang.' But you might say, 'I need an SUV, or a minivan.'"

Claude Brodesser-Akner may be reached at cbrodesser@njadvancemedia.com. Follow him on Twitter @ClaudeBrodesser. Find NJ.com Politics on Facebook.