WASHINGTON, DC - FEBRUARY 07:  U.S. Senate Majority Leader Sen. Mitch McConnell (R-KY) (L) walks towards the Senate chamber at the Capitol February 7, 2018 in Washington, DC. Sen. McConnell and Senate Minority Leader Sen. Chuck Schumer (D-NY) announced that they have reach agreement on a two-year budget deal.  (Photo by Alex Wong/Getty Images)
WASHINGTON, DC - FEBRUARY 07: U.S. Senate Majority Leader Sen. Mitch McConnell (R-KY) (L) walks towards the Senate chamber at the Capitol February 7, 2018 in Washington, DC. Sen. McConnell and Senate Minority Leader Sen. Chuck Schumer (D-NY) announced that they have reach agreement on a two-year budget deal. (Photo by Alex Wong/Getty Images)
PHOTO: Alex Wong/Getty Images North America/Getty Images
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Editor’s Note: Paul Begala, a Democratic strategist and CNN political commentator, was a political consultant for Bill Clinton’s presidential campaign in 1992 and was counselor to Clinton in the White House. He was a consultant to Priorities USA Action, which was a pro-Obama super PAC before it was a pro-Hillary Clinton super PAC. The opinions expressed in this commentary are his. View more opinion articles on CNN.

(CNN) —  

Once in a while, a politician becomes so powerful and yet so destructive that he or she does real damage to the branch of government in which she or he serves.

Obviously, Richard Nixon damaged the presidency, Newt Gingrich turned the House of Representatives into a mixed martial arts arena, and Roger Taney forever stained the Supreme Court with the Dred Scott decision. But it takes someone special, someone rare, someone spectacularly Machiavellian and malevolent, to screw up all three branches of government.

Ladies and gentlemen: Mitch McConnell. The soft-spoken Kentuckian has, in just a few short years, done lasting damage to the presidency, the Senate and the Supreme Court: the hat trick of democracy destruction.

To wit:

The presidency. American intelligence knew Vladimir Putin’s henchmen were attacking America, using cyberwarfare tactics to undermine Hillary Clinton’s campaign. Yet when the nonpartisan leaders of our intelligence community briefed McConnell, his reply – according to a new book by Washington Post reporter Greg Miller – was purely partisan: “You’re trying to screw the Republican nominee.” McConnell not only refused to condemn the Russians, Miller writes, he threatened to attack the US intelligence community, labeling its call to defend America an act of partisan politics.

By helping hobble our defense against the dark arts of Putin, McConnell has tainted Donald Trump’s presidency. The noted media scholar Kathleen Hall Jamieson has carefully examined the Russian effort, and has concluded that without Russia’s help, Trump would not be President.

Trump’s legitimacy is questionable – in part because McConnell refused to defend our presidential electoral system when it came under foreign attack.

The Senate. McConnell has broken the Senate. By refusing even to meet with President Barack Obama’s Supreme Court nominee, Judge Merrick Garland, and by blocking hearings on his nomination, McConnell deeply harmed the comity on which the Senate is supposed to run.

I am amused by the notion that, somehow, former Democratic Majority Leader Harry Reid is the one who broke the Senate when he eliminated the filibuster for lower court judgeships. Right. If only Reid had been nicer to sweet ol’ Mitch, then he wouldn’t have been so doggone mean when he got power.

In truth, Reid had no choice but to limit the filibuster on lower court nominations, given McConnell’s abuse of it. McConnell invoked the 60-vote rule to block Obama’s nominees nearly as often as it had been used in all previous US history. Under all the presidents before Obama, 86 nominations had been blocked by filibuster. In just the Obama presidency alone, McConnell used the filibuster to block 82.

McConnell’s naked partisanship has crippled the Senate. One wonders how it will ever recover.

The Supreme Court. Which brings us to the high court. Not content with simply stealing Garland’s seat for Trump, McConnell rammed through the nomination of the profoundly unpopular Brett Kavanaugh. The court now has four justices appointed by Presidents who originally came into office after losing the popular vote.

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(To be fair, George W. Bush nominated Chief Justice John Roberts and Justice Samuel Alito in his second term after winning the 2004 election fair and square. But does anyone think he would have had a second term if the court had not installed him despite the will of the voters in 2000?)

The McConnell court is now every bit as partisan as one of the panels on my old show, “Crossfire.” Except on “Crossfire,” we didn’t wear robes and pretend we were somehow above the fray. For decades to come, American citizens upset about any erosion of their constitutional rights – civil rights, LGBTQ rights, voting rights, women’s rights, reproductive rights, consumer rights, environmental protections – can thank McConnell.

Legacies are often hard to predict when a politician is still in office. Not this time. When you see bitter, hateful, vengeful hyperpartisanship infecting our national life – from the White House to the Senate to the marble palace of the Supreme Court – you can thank the “Gentleman from Kentucky.”