Why haven't Trump's tax returns, Clinton's speech gotten the Romney treatment?

Here's what Mitt Romney said without actually saying it when he called for Donald Trump to release his tax returns: The media pressure made me do it four years ago, and now it's Trump's turn.

Why else would the 2012 Republican presidential nominee make the exact same implication that was at the heart of every story about his own reluctance to open the books - that a wealthy candidate who doesn't make his returns public might have something to hide?

It's surely not because he truly believes, as he told Fox News Channel's Neil Cavuto on Wednesday, that "voters have a right to see those tax returns before they decide who our nominee ought to be." If that were a firmly held principle of Romney's, he wouldn't have resisted releasing his own tax returns throughout his career in politics, dating back to his 1994 Senate bid in Massachusetts.

Romney knows that principle - voters' "right to see" - won't move Trump, because it never moved him. The only thing that might make this year's Republican front-runner give in on his tax returns - or, for that matter, make Hillary Clinton release the transcripts of her Goldman Sachs speeches - is the kind of relentless media questioning that Romney faced in the last election.

In case you've forgotten, the heat was intense. Even when he released his 2010 tax return, a two-year income summary and an estimate for 2011, the press was not satisfied. The media often pulled the dad card, noting that George Romney had released 12 years of tax returns when he sought the 1968 GOP nomination. Harry Reid helped move things along by trafficking in later-disproven rumors that Mitt Romney might not have paid any taxes for 10 years.

Journalists dogged Romney for more documentation long past the stage of the race we're in now - past the Republican National Convention, in fact - until he made a second disclosure in September 2012, giving out his 2011 return.

There are good reasons why a super-rich candidate's tax returns are of public interest - reasons that Romney himself articulated well when discussing Trump and the rest of the Republican field:

"This would give us a real sense of whether these people are on the up and up and whether they've been telling us things about themselves that are true or not.

"Frankly, I think we have good reason to believe that there's a bombshell in Donald Trump's taxes. I think there's something there. Either he's not anywhere near as wealthy as he says he is or he hasn't been paying the kind of taxes we would expect him to pay, or perhaps he hasn't been giving money to the vets or to the disabled like he's been telling us he's been doing."

The same basic rationale could be applied to the transcripts of three speeches Clinton delivered to Goldman Sachs between her tenure as secretary of state and her entry in the presidential race - for which she was paid a combined $675,000. Clinton insists that, despite those speaking fees and the campaign contributions she receives from the banking sector, she is prepared to be tough on Wall Street as president.

That might well be true, but what she said behind closed doors to a bunch of bankers might be more revealing than what she says on the campaign trail. To paraphrase Romney, we might learn whether she's been telling us things about herself that are true or not.

Still, the media pressure on Clinton and Trump hasn't come close to what Romney faced. Unsurprisingly, neither has volunteered to produce the documents in question. Trump said Wednesday that he'll decide in the next couple of months whether to release his tax returns.

And Clinton spokeswoman Karen Finney made clear on Thursday that the Democratic favorite has no plans to release the transcripts. The candidate herself said in a CNN town hall on Tuesday that she would release her speech transcripts if all the other candidates did the same.

Until the media give Clinton and Trump the Romney treatment, we're not likely to get what we're looking for. Candidates don't give out information they'd prefer to keep private simply because it's the right thing to do; they do it because scrutiny eventually makes them feel like they have no choice.

It's not happening yet. Maybe it's a general election thing.

Previously:

• 02/08/16: In media coverage of Chelsea Clinton, the kid gloves are still on

Comment by clicking here.