Wondering why money for campaign ads — the lack of which sunk Rick Santorum in 2012 — doesn’t seem to be making much of a difference this year?

The New York Times helpfully measures the value of the “earned media” Donald Trump gets (i.e. free television appearances): $1.9 billion.

That’s $1.6 billion dollars more than the next GOP candidate, Ted Cruz.

Why spend money on campaign ads when the networks will give you an hour of free coverage of your press conference on election night, to give just one example.

It draws more ratings, as Trump points out, and they are in business to make money.

If you added in the value of Rush Limbaugh, Laura Ingraham, and all the other radio hosts who have focused primarily on lauding and covering Trump, it’s priceless.

Maggie Gallagher is a senior fellow at the American Principles Project and can be followed on Twitter @MaggieGallaghe.