If America really is in the midst of a constitutional crisis, Democrats have a funny way of showing it. While President Trump continues act with virtual impunity in the face of congressional oversight, congressional leadership is dithering. Who will step up to hold the president of the United States to normal standards of accountability and transparency?

State legislatures are trying to offer an answer.

Let's back up. On Wednesday, the House Judiciary Committee voted to hold Attorney General William Barr in contempt, after he failed to turn over an unredacted version of Special Counsel Robert Mueller's report about his investigation into links between the Trump administration and Russia. Barr's refusal is part of a wider effort by President Trump to resist all inquiries from the Democratic-led House — an effort that essentially neuters the very concept of congressional oversight.

It was a serious moment, and House Judiciary Chair Jerrold Nadler (D-N.Y.) treated it as such.

"We've talked for a long time about approaching a constitutional crisis," Nadler said. "We are now in it."

Fine talk. But Nadler almost immediately diminished the force of his words by shying away from one of the prime options Congress has to address such crises: impeachment. Such a measure, he said, may "not be the best answer in this constitutional crisis."

That sound you just heard was a thousand Democratic activists groaning in frustration. Even as Trump's challenges to the power and prerogatives of Congress have grown more bold, party leaders in Washington, D.C., have seemingly tried everything they can to avoid committing to impeachment, for fear of an electoral backlash. On Wednesday, House Speaker Nancy Pelosi (D-Calif.) called Trump's behavior "self-impeachable" — but that's not how the process works: Impeachment requires action by the House that she leads.

The Trump administration's refusal to hand over the president's tax returns is, of course, another piece of the constitutional crisis facing Congress — a fact much on the minds of New York legislators. While Pelosi and Nadler were dancing around the possibility of impeachment on Wednesday, the New York State Senate passed a bill that could force Trump's tax returns into public view. The proposed law would let committee leaders in the U.S. House of Representatives seek the state tax returns of public officials, so long as the request was made for a "legitimate legislative purpose." (Trump is a New York resident, and files taxes in that state.) It would apply to returns filed by any statewide elected official, including a U.S. president and vice president, as well as the state's U.S. senators.

"Our system of checks and balances is failing," the bill's sponsor said. "New York has a special role and responsibility to step into the breach."

New York isn't the only state taking action to challenge Trump directly. California's state Senate last week passed a bill requiring presidential candidates to furnish their tax returns as a condition for getting on the presidential primary ballot. "We believe that President Trump, if he truly doesn't have anything to hide, should step up and release his tax returns," said state Sen. Mike McGuire, a Democrat who co-sponsored the bill.

That may not sound like a big deal, since Trump seems likely to weather any primary challenge his campaign is unable to stamp out, and he has no chance at claiming California's electoral votes anyway. In other words, he can afford to ignore the state. The president's problem, though, is that similar legislation has been contemplated in at least 18 states this year. Even if Trump can win the Electoral College without Democratic-leaning states that pass such bills, his absence from those ballots would be one more wound to the appearance of his democratic legitimacy.

States, of course, have been at the vanguard of resistance since the beginning of Trump's presidency. Attorneys general have banded together to challenge policies like the so-called "Muslim ban," while states like California have aggressively passed laws designed to mitigate the administration's widespread regulatory rollback.

Those efforts have been valuable — but they are insufficient. "If they won't do it, New York can," a state legislator said of Congress' inability to gain the president's compliance. That's a noble, gutsy statement, but it's also not entirely true. Trump is not just a problem for California or New York or any other individual state. He poses a challenge to the continued democratic functioning of our federal government. Ultimately, this problem can only be truly resolved at that high level.

America is in a constitutional crisis. The states have played an admirable role in pushing back against the administration. But sooner or later, congressional Democrats are going to have to be as brave and stout as their counterparts back home and challenge the president directly. No matter what Pelosi says, Trump isn't going to impeach himself.