I usually say that the media care far more about endorsements than the voters do.

Sarah Palin backing Donald Trump might be different.

At the very least, the surprise move enables Trump to dominate the next few news cycles in this crucial home stretch before the Iowa caucuses.

And coupled with Iowa Gov. Terry Branstad coming out against Ted Cruz, it gives Trump a sense of momentum in a race where a week or so ago he was thought to be slipping. (Branstad is ripping Cruz for taking the bold step of criticizing ethanol subsidies, which tells you what you need to know about Iowa politics.)

In her speech, Palin mocked the GOP establishment for calling Trump insufficiently conservative and saying it's "busted" for attacking its own front-runner, offering her highest praise that he was “going rogue” against the party. 

Nearly eight years after her losing vice presidential race, Palin is not the political force she once was. But she validates Trump among very conservative and evangelical voters, precisely the kind who turn out on wintry February nights in Iowa.

Palin put her muscle behind Joni Ernst in Iowa’s 2014 Senate race, and that helped the tea party favorite win. And as Cruz acknowledged in a graceful preemptive message, he wouldn’t have won his Senate seat in 2012 without Palin’s backing.

It remains to be seen whether Palin actively campaigns for Trump for more than a day, but in the Facebook age, it doesn’t really matter. 

Palin’s mama grizzly backing also helps neutralize Hillary Clinton’s dismissal of Trump as a sexist figure.

Palin has more than her share of detractors, many of them in the media. Some of them will paint both Palin and Trump as loudmouths who don’t know a hell of a lot about policy.

But this isn’t a general election endorsement. With Cruz attacking Trump as a “fake conservative,” her embrace helps reassure conservative voters that he’s the real deal.

You can see why they’d like each other. Both are media-savvy mavericks who challenged the political establishment and have had to fend off criticism about the depth of their knowledge. And they’ve both had reality shows!

Palin, who served half a term as Alaska governor, is more of a cultural figure now, and Trump is a celebrity businessman who made the leap to politics.

As an interesting side note, Palin is making this move despite Trump having dismissed the POW record of the man who brought her to national prominence, John McCain. But in the finger-pointing that followed the 2008 loss, there was little love between the McCain and Palin camps. Besides, McCain has made clear he’s not a fan of the senator he once called a “wacko bird,” and more recently echoed Trump in questioning Cruz’s eligibility on birther grounds.

Cruz’s strongest shot at the nomination relies on an Iowa win that helps deflate the Trump balloon. That path may have just gotten a bit more complicated.

Howard Kurtz is a Fox News analyst and the host of "MediaBuzz" (Sundays 11 a.m. and 5 p.m. ET). He is the author of five books and is based in Washington. Follow him at @HowardKurtz. Click here for more information on Howard Kurtz.