WASHINGTON ― House Republican leaders managed to derail a House floor vote last week on impeaching the commissioner of the Internal Revenue Service, but Donald Trump may wish they also squashed a hearing Wednesday on whether or not impeachment was a good idea.

That’s because Democrats hijacked the hearing with Commissioner John Koskinen when they got their chance to speak, and managed to skewer Trump’s refusal to release his taxes.

One Democrat, Rep. Luis Gutierrez (D-Ill.), elevated the exercise to A-level trolling by opening his round of questions while munching on a bag of Skittles in a reminder of Donald Trump Jr.’s recent gaffe about Syrian refugees and the likelihood that they “would kill you.”

But that was just pointed mockery.

The larger point was to turn a hearing that Democrats deemed a political stunt into a display that instead raised the serious issue of the Republican presidential nominee’s refusal to disclose his taxes.

All presidential nominees since the 1970s have released their tax returns, but Trump says he cannot unveil his because they are being audited by the IRS.

Plenty of pundits have called the excuse phony, so Democrats decided to nail it down with Koskinen.

Although the commissioner refused repeatedly to get into specific talks about Trump, Democrats got him to make the general point.

“Is there anything that would prohibit someone from releasing tax returns, if they want to, because they’re under audit?” Rep. Jerry Nadler (D-N.Y.) asked.

“No,” Koskinen answered.

The answer was the same when Rep. Ted Deutch (D-Fla.) wanted to know if there was anything that would stop someone from proving that they are in fact being audited by releasing the audit letter they got from the IRS.

“Would releasing the person’s tax return during the audit in any way impact that pending audit of the return?” Deutch asked.

“The release itself wouldn’t. The concern sometimes by taxpayers is that when the information is public there may be more information that will be discovered or provided,” Koskinen said.

“That is the concern,” Deutch agreed, sounding somewhat pleased with the admission. “We understand that is the concern.”

Democrats then went on to highlight some of the items that could prove problematic for Trump to disclose, such as his actual income, what he pays the government in taxes, clues to his actual net worth and records of his charitable giving.

Rep. Zoe Lofgren (D-Calif.) wondered aloud if discovering payments by Russia might suggest a monetary ― or even treasonous ― motive for going soft on a U.S. rival.

Several also raised the recent reports of Trump using his tax-free foundation to to buy paintings and sports memorabilia, to fund political campaigns and to pay business expenses.

“Is it appropriate for a foundation to give political donations?” asked Rep. Sheila Jackson Lee (D-Texas).

The answer was no.

Gutierrez focused specifically on Trump using foundation money to pay legal expenses and to buy a portrait.

“Given that scenario, is that strictly speaking ― what’s the term ― legal?” Gutierrez asked.

Koskinen declined to respond to anything remotely specific, but was willing to lay out the basic law.

“Any tax-exempt organization cannot use its money to benefit anyone who’s closely associated with that organization,” Koskinen said.

And while he said repeatedly that he would not talk about any individuals, Democrats were happy to suggest a certain GOP candidate may wind up with some serious problems with the taxman.

“Commissioner, you know who I’m talking about. Everyone in this room knows who I’m talking about,” said Gutierrez, who had made clear at the start of his questions to Koskinen that he was going to enjoy his chance to derail the GOP’s hearing.

“I have a few extra bags of Skittles and I’m going to share them with you and your staff so that after this reckless and bitter hearing you can get a small amount of sweet candy to improve the rest of your day,” Gutierrez said.

Editor’s note: Donald Trump regularly incites political violence and is a serial liar, rampant xenophobe, racist, misogynist and birther who has repeatedly pledged to ban all Muslims — 1.6 billion members of an entire religion — from entering the U.S.