Let’s pause to consider the rich irony of Mitt Romney demanding Donald Trump’s back taxes

The latest attack on Donald Trump from establishment Republicans comes from 2012 Republican nominee Mitt Romney. And given the messenger, the attack is ironic: Romney says Trumps's tax returns are hiding a "#bombshell."

The pressure made its way to the debate Thursday night, where Trump said he can't release the returns because he's being audited. (That does not appear to be legally accurate.)

Trump's tax returns have been the subject of feverish speculation since he got into the race. For one, they'd give a better idea of how much money Trump actually has. And that's one reason the Republican frontrunner has fought against releasing them, even when it seems like it would be helpful to do so — like after he sued a New York Times reporter for libel for saying Trump's worth was in the millions, not billions.

Romney has plenty of experience with accusations that something nefarious is hiding in tax returns — though the last time around, he was on the other side. In 2011, the future Republican nominee faced months of pressure from both Republican rivals and Democrats to release his returns.

That pressure ramped up after then-Senate Majority Leader Harry Reid said in August 2012 that he'd heard Romney had paid no taxes at all for 10 years.

This was not true. (And Reid is unrepentant: "Romney didn't win, did he?" Reid said to CNN's Dana Bash in 2015.) Romney eventually disclosed two years of his tax filings, plus, in the September before the election, a summary of 20 years of his tax rates.

So it's more than a little ironic that Romney is now the one demanding multiple years of tax returns and suggesting a failure to disclose them means Trump could be hiding something.

On the other hand, Romney can argue he's the ideal messenger for this attack — because he knows the damage that speculation about taxes can do. (Or as he laconically put it: "Became issue.")