Mitt Romney’s insistence on shielding his tax returns has become so untenable that he can’t even make the sale to National Review.

Hours after Romney told the conservative magazine that he is “simply not enthusiastic” about giving Barack Obama’s oppo researchers “hundreds or thousands of more pages to pick through, distort, and lie about,” its website scolded him in an editorial.

His stance looks “unsustainable,” the website said, and “in all likelihood, he won’t be able to maintain a position that looks secretive and is a departure from campaign conventions. The only question is whether he releases more returns now, or later.

With other conservatives piling on, Romney finds himself in a tax trap that is partially of his own making.

“Why they didn’t release more of this material a year ago is confusing to me,” says Mike Murphy, a veteran GOP consultant who has worked for Romney in the past. “But we’re reaching a tipping point in which the press is showing a double standard. The press has so bought into the class-warfare narrative—even though there are lots of millionaires in the U.S. Senate—that harping on this issue in an almost obsessive way betrays a little bias.”

Even if the media are piling on—and it’s hard to avoid the story when Obama and all his surrogates are pounding it day after day—the net result is that the Romney team is on the defensive, day after day. Whatever message he wants to deliver has been drowned out by the drumbeat.

“This is a tactic by the Obama campaign to change the topic,” says John Brabender, the chief strategist for Rick Santorum’s presidential campaign. “Romney should say, ‘I’m not going to let them do that, and any time you hear the word ‘tax,’ I’m going to say ‘this guy gave us the biggest tax increase in history,’” referring to Obamacare.

“This is a rabbit hole.”

Romney is caught between two unpleasant outcomes. If he sticks to his guns, he will continue to get hammered day after day—perhaps through November—for hiding his finances, with all kinds of speculation about what damaging information might be contained therein. If he caves and puts out more returns beyond the one year he’s already released, he gives the Obama camp lots of raw material to feast upon—but has a shot at taking the hit and moving on.

What’s striking is that a number of prominent commentators on the right agree—and their views can’t be so easily dismissed.

“He should release the tax returns tomorrow,” Weekly Standard Editor Bill Kristol said on Fox News on Sunday. “It’s crazy. You’ve got to release six, eight, 10 years of back tax returns.”

And George Will was withering on ABC: “Oh, Mitt Romney is losing at this point in a big way. If something's going to come out, get it out in a hurry. I do not know why, given that Mitt Romney knew the day that McCain lost in 2008 that he was going to run for president again that he didn’t get all of this out and tidy up some of his offshore accounts and all the rest.”

Of course, most righty pundits rooted against Romney in the primaries. Still, there’s a note of incredulousness in these comments: How on earth did a man who ran for president four years ago allow himself to get boxed in like this? After all, voters already know Romney is a wealthy guy with tax shelters. Is what’s in the past returns so bad that it is worth this kind of drubbing?

What’s more, Romney has been through this before, at the hands of Republicans. During a primary debate, Newt Gingrich said: “If there’s anything in [the returns] that is going to help us lose the election, we should know it before the nomination.... And if there’s nothing in there—if there’s nothing in there, why not release it?” After vowing not to do so, Romney relented and put out one year’s return—sparking unfavorable comparisons with his father, George, who released 12 years’ worth when he ran for president in 1968.

Now he’s waging the same war under an even more intense spotlight.

“The Romney campaign has come to the conclusion they can fight this with the Obama camp with hand-to-hand guerrilla warfare," Brabender says. “It totally takes you off-message. He needs to provide a better picture of what the future will be like under Romney. Obama has made this a referendum on a mediocre president vs. The Man, and people like to stick it to The Man.”

One thing is abundantly clear as the negative headlines pile up during the dog days of July: The Man needs to change the narrative, and fast.