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(CNN) —  

Here’s a warning from history that you won’t hear from people pushing for President Trump’s impeachment.

Most commentators keep comparing Trump’s impeachment crisis to Richard Nixon and Watergate, Bill Clinton and Monica Lewinsky or even a lesser-known President, Andrew Johnson.

But if his critics want to justify booting Trump out of office, here’s the president they should cite for historical inspiration: Ulysses S. Grant.

Yes, that Grant. The rumpled, cigar-chomping, 19th-century general who led one of the most corrupt administrations in US history and was once called a “drunken butcher.”

Grant is not the go-to president for commentators when talk turns to impeachment. Yet he did something one night during a famous Civil War battle that offers a fresh historical analogy for those weighing whether Democrats should “damn the torpedoes” (another line from a famous Civil War battle) and sanction Trump for appearing to solicit foreign interference in a US election.

Grant’s pivotal moment came when the country was even more divided than it is now. He was confronting a wily opponent who had already displayed a Trumpian ability to get away with “outrageous” battlefield decisions that would have doomed any other commander.

Grant’s message

In May of 1864 Grant came up against the legendary Confederate commander, Gen. Robert E. Lee. Their armies collided in a nightmarishly dense forest in Virginia in what became known as “The Battle of the Wilderness.”

Grant wasn’t just fighting Lee’s army. He was also battling Lee’s reputation. The Southern general had already befuddled Union commanders after what one historian called a series of “outrageous victories.” Among them was the battle of Chancellorsville, where Lee broke a cardinal rule of warfare: He divided his outnumbered army in the face of the enemy – and still won.

One night during the Battle of the Wilderness, Grant’s officers rushed into his tent in a panic, warning him what Lee might do if they attacked.

Confederate Gen. Robert E. Lee stands for a portrait April 16, 1865 in Richmond, Virginia.
Library of Congress/Getty Images
Confederate Gen. Robert E. Lee stands for a portrait April 16, 1865 in Richmond, Virginia.

The normally unflappable Grant lost his temper.

“Oh, I am heartily tired of hearing about what Lee is going to do,” Grant said, according to acclaimed Civil War historian Shelby Foote. “Some of you always seem to think he is suddenly going to turn a double somersault, and land in our rear and on both of our flanks at the same time. Go back to your command and try to think what we are going to do ourselves, instead of what Lee is going to do.”

Grant’s armies pressed on. In less than a year, Grant had defeated Lee and the Civil War was over.

If, as the adage goes, “War is a mere continuation of policy by other means,” Democrats could learn this from Grant:

Think less about what Trump is going to do and focus on what you’re going to do.

Some psychologists have a name for what Grant’s subordinates experienced. They call it “paralysis by analysis,” when people can’t act decisively because they’re so afraid to make a wrong decision. Sports fans see it all the time in athletes or teams who lose because they overthink.

Those pushing for Trump’s impeachment are also hearing a lot of nervous chatter. Some doubters warn that pursuing impeachment will only rile up Trump’s base even more by claiming “liberal elites screw people like us.”

One New York Times columnist said the prospect of impeaching Trump “terrifies me” because an unscrupulous Trump is capable of doing virtually anything to “vent his fury or distract the audience.”

A defiant President Donald Trump speaks during a news conference at the White House on October 2.
Carolyn Kaster/AP
A defiant President Donald Trump speaks during a news conference at the White House on October 2.

And since this is a week for Civil War analogies, Trump issued his own warning from history as well.

He tweeted a version of a warning from an evangelical pastor who said that if Democrats remove Trump from office, “It will a cause a Civil War-like fracture” from which America will never heal.

’Moral courage’ in war – and politics

Yet many Democrats are getting in touch with their inner Grant. They’re recommending moving quickly and decisively for impeachment.

“We should be focused and not overthink this,” said Rep. Eric Swalwell, a California Democrat and a member of the House intelligence panel.

House Speaker Nancy Pelosi, the Democratic leader, is also rallying her troops. She was recently asked if impeachment could backfire.

House Speaker Nancy Pelosi and House Intelligence Committee Chairman Rep. Adam Schiff speak at a news conference October 2 on Capitol Hill.
Susan Walsh/AP
House Speaker Nancy Pelosi and House Intelligence Committee Chairman Rep. Adam Schiff speak at a news conference October 2 on Capitol Hill.

“It doesn’t matter,” she said. “We handled this with such care. It isn’t like we ran into this. He has taken us to this place. He has given us no choice. Politics has nothing to do with impeachment, in my view.”

Such an answer might have made Grant proud. In a memoir he completed just days before he died, the 18th president said he adm