WASHINGTON — In 2017, Senate Minority Leader Charles Schumer, D-N.Y., accused President Trump of showing "a disdain for an independent judiciary that doesn't always bend to his wishes" after Trump criticized a federal judge who ruled against his administration. Senate Democrats, by contrast, have launched an unprecedented attempt to actually bend the Supreme Court to their wishes — threatening to restructure the court if the justices do not rule as they see fit.

The threat came over the Supreme Court's decision to hear a challenge to New York City's restrictions on how gun owners who have residential permits can transport their guns. In a legal brief, Sens. Sheldon Whitehouse, D-R.I., Mazie Hirono, D-Hawaii, Richard Blumenthal, D-Conn., and Kirsten Gillibrand, D-N.Y., argued that the case against New York was moot because it had rescinded the gun regulations in question.

What is not acceptable is openly threatening the court with political retribution if it does not rule a certain way. That is precisely what these Senate Democrats did. "The Supreme Court is not well," they wrote. "And the people know it. Perhaps the Court can heal itself before the public demands it be 'restructured to reduce the influence of politics.'" As all 53 Senate Republicans wrote in a letter to the court last week, "the implication is as plain as day: Dismiss the case, or we'll pack the Court."

Talk about disdain for an independent judiciary! Can you imagine if Trump issued such a preemptive threat? Heads would explode.

The judicial left has gone off the deep end because it is losing its battle for an activist liberal court. When Justice Antonin Scalia died in 2016, they saw a once-in-a-lifetime chance to shift the ideological direction of the court for a generation. By appointing two conservative justices, Trump has thwarted those dreams. And now they are worried, due to concerns over Justice Ruth Bader Ginsburg's health, that Trump might get a third appointment. So, many Democrats are now openly talking about adding more justices if they gain power.

Those threats will backfire, because they dramatically raise the stakes in the 2020 election. In 2016, over a quarter of Trump voters said that the Supreme Court was the most important factor in their decision to support him. With Trump already having secured a conservative majority on the court, his ability to appoint justices was shaping up to be a less powerful argument this time around. But now that Democrats have threatened to pack the court with liberal judges if they win the White House and the Senate, the Supreme Court will once again be front and center. For the president, this is a massive stroke of luck.

Follow Marc A. Thiessen on Twitter, @marcthiessen.