Because they can't win if they don't cheat

Ever since the 1960s, Republicans have been painting Democrats, with varying degrees of subtlety and stridency, as the party of soft-on-defense, unpatriotic criminal coddlers. The particulars of the indictment have changed, but the general attitude of contempt for, and alarm about, “liberals” as a threat to ordinary Americans has remained remarkably constant.

  WaPo

"Conservative" has never been used with contempt and accusation the way "liberal" has.

President Trump, a political tuning fork par excellence, has channeled this resentment and amplified it to ear-splitting decibels. He snarls that Democrats are “treasonous,” “un-American,” “evil” — an “angry left-wing mob” bent on turning our country into a bankrupt socialist dictatorship like Venezuela. Leading Republicans, rather than rebuke this intemperate rhetoric, echo it: Former House speaker Newt Gingrich says Democrats want to “destroy America.”

[...]

If you think the opposition poses an existential threat to the United States, [...] concepts such as fair play, decency, democratic norms, even the rule of law can seem like anachronisms that you can’t afford in a battle against the spawn of Satan.

Which bring us to the Republican assault on democracy in North Carolina, Wisconsin, Michigan, and, most importantly, Washington.

[...]

Two years ago, Republicans in control of the North Carolina legislature took away key authorities from a newly elected Democratic governor. That playbook is now being applied in Wisconsin and Michigan. In both states, Republican-controlled legislatures elected with the help of outrageous gerrymandering (Wisconsin Democrats won 54 percent of the statewide vote but only 36 of 99 Assembly seats) are moving to strip important powers from incoming Democratic governors.

[...]

To be sure, Democrats are hardly blameless in anti-democratic shenanigans. In Massachusetts, the state legislature stripped then-Gov. Mitt Romney (R) of the power to fill a vacant U.S. Senate seat and then restored that authority to Democratic Gov. Deval Patrick. But, as Matt Glassman of Georgetown University argued in a Post analysis, the two parties are not equally culpable. Just as Republicans have moved further to the right than Democrats to the left, so too Republicans are more likely to engage in what scholars have labeled “constitutional hardball” — disregarding democratic norms to seize and retain power. Law professors Joseph Fishkin and David Pozen document this disparity in a law review article noting previous GOP assaults on democratic norms, which include the Supreme Court ruling that handed George W. Bush the presidency, repeated government shutdowns to push their agenda and Senate Majority Leader Mitch McConnell’s (R-Ky.) refusal to schedule a vote for Supreme Court nominee Merrick Garland.

[...]

The law, in Republicans’ view, applies only to their opponents. They’re still chanting “Lock her up” years after the FBI determined that there was not enough evidence to prosecute Hillary Clinton. Trump recently retweeted a graphic showing his leading critics behind bars for “treason.” And Gingrich asserts, without any evidence, that former FBI director James B. Comey should be prosecuted for a “whole series of felony charges.”

[...]

All too many Republicans are going from opposing the Democratic Party to opposing democracy itself. They are becoming an authoritarian party.

[...]

David Frum wrote in “Trumpocracy: The Corruption of the American Republic”: “If conservatives become convinced that they cannot win democratically, they will not abandon conservatism. They will reject democracy.”

As we see regularly.