Ever since Donald Trump came down that Trump Tower escalator to announce his candidacy for president, we’ve heard a great deal about the abuse of norms — constitutional norms, democratic norms, norms of decency, all kinds of norms. For Trump supporters, the president’s frequent violations of norms, while occasionally regrettable, were for the most part welcome because they proved he was willing to fight to win. This was necessary, the theory went, because the left didn’t care about norms anymore, they only cared about winning.


But this view — that the other side plays dirty so we must too — is hardly new to American politics. The sentiment is practically baked into politics. But the degree and intensity of the baking has increased and has come to define whichever side has been out of power over the last few decades.


President Clinton’s impeachment on charges of lying under oath to a federal grand jury and obstructing justice came after years of frustration with what was perceived as “Slick Willie’s” flouting of political norms. The 2000 presidential election recount in Florida and the Supreme Court’s role in settling the Bush-Gore recount dispute was all the evidence progressive online activists (called the “netroots” in pre-Twitter nomenclature) needed to argue that Democrats needed “fighting Dems” to play as dirty as they imagined Karl Rove, Bush’s supposed Rasputin, was playing.


Partisans invariably think the other side is cheating perhaps just a little bit more than they really are, so when they decide to fight fire with fire, they emulate the worst-imagined tactics of the enemy, creating a race-to-the-bottom dynamic.


And that brings us to the Democrats’ rush to create a “constitutional crisis” where there isn’t one. Last week, the House Judiciary Committee voted to hold Attorney General William Barr in contempt of Congress for refusing to hand over a fully unredacted version of the Mueller report in compliance with a subpoena.


It’s a wild overreaction given that Barr’s decision to release the Mueller report almost in its entirety was purely discretionary. By law, and by custom, Barr was under no obligation to release anything since the norm is for the Department of Justice to stay silent if it fails to find prosecutable crimes. His only objectionable transgression against traditional norms was offering a Trump-friendly memo accurately, if tendentiously, summarizing the report’s conclusions.


That was enough for Democrats to lock in to a “cover-up” narrative. Never mind that Barr soon waived all executive privilege claims and released the whole report, redacting only a sliver of material that relied on confidential grand jury testimony and a few sentences that might reveal sources and methods of intelligence gathering. The latter is stuff the Russians would presumably love to see, the former is stuff Barr is barred by law from releasing. If you read the report — and by the fact that you can read it — it’s clear there was no cover-up.


As a compromise, Barr invited congressional leaders to look at an even more unredacted version. Rep. Jerrold Nadler (D-N.Y.), chairman of the House Judiciary Committee, refused to even look at the report, saying a 99.9 percent redaction-free report wasn’t good enough. The notion that a few sentences of blacked out information are the real “smoking gun” is absurd.


Instead of praising Barr for releasing to the public what amounts to an off-the-shelf roadmap for impeachment, Barr is not only being charged with contempt, but Democrats are cavalierly talking about throwing Barr in jail.


The Democrats are on much better legal footing in their pursuit of the president’s tax returns, but even here the effort amounts to responding to one violation of norms with another.


Trump should have abided by custom and released his returns, as past presidents have done and as he said he would. But the law says Congress can demand to see them. The law is a bad one prone to abuse, but the Trump administration will still have to comply. But in listening to Democrats explain why they want the returns, you can see how corrupting the desire to get Trump has become.


On MSNBC’s “Morning Joe,” Rep. Bill Pascrell Jr. (D-N.J.) offered his reason for wanting the tax returns: to rub the truth in the faces of “the people who follow Mr. Trump, his base.” Pascrell wants them to say, “We’ve been had.” “I can’t wait for that to happen,” he added.


Pascrell will be sorely disappointed by the capacity of Trump’s base to absorb negative revelations about the president. But that’s beside the point. The White House is wrong when it claims Congress must have a “legislative purpose” to see the returns. But democratic norms suggest that Congress shouldn’t require confidential tax returns to be spilled out just for the purpose of saying “nyah, nyah” to voters or to prove that Democrats are just as willing to fight dirty.


Jonah Goldberg’s latest book, “Suicide of the West,” is now available wherever books are sold. You can write to him in care of this newspaper or by e-mail at goldbergcolumn@gmail.com, or via Twitter @JonahNRO.