President Jimmy Carter emerged from a contested Democratic primary in 1980, at a time when unemployment exceeded 8 percent and interest on some loans topped 15 percent.

The economy was contracting, while the Iran hostage crisis made the United States look weak.

Yes, Ted Kennedy was a flawed candidate who wouldn’t have gotten as far as he did without the family name. But Carter’s eventual primary victory — he lost to Ronald Reagan in the general election — shows the power of the presidency when competing against candidates in your own party.

In 2020, Donald Trump is likely to be running at a time of record-low unemployment, low interest rates and no one named Bush on the GOP primary ballot. Too close to Putin? Carter survived the primary even after accepting one of those European cheek kisses from Leonid Brezhnev, who double-crossed the U.S. president six months later with the Soviet invasion of Afghanistan.

(Reagan was smart enough to adopt the slogan, “You, too, can kiss off Carter.”)

Like Carter, Trump does have competitors. Former Congressmen Joe Walsh and Mark Sanford, along with former Massachusetts governor Bill Weld, have entertained challenges to Trump in the GOP presidential primary season. To say these are long-shot, dark-horse candidates is putting it mildly.

Yet Kansas and two others states are not holding GOP caucuses or elections in 2020, a move that is not without precedent. In 2004, 10 states canceled their GOP nominating contests, when President George W. Bush was seeking a second term.

This is the wrong move, for the obvious reasons of limiting voter choices and creating an impression of weakness. What’s more, it’s unnecessary. Trump enjoys 88 percent support among Republicans, according to a Gallup poll. Say what you want about his policies, but America doesn’t appear weak.

The bigger problem in avoiding a primary contest is it degrades candidates in other races by making the GOP appear to be the party of Trump rather than a party of ideas. This might provide a short-term boost, but it is a move fraught with long-term drawbacks because at some point someone other than Trump has to emerge as the party’s leader.

That point begins no later than January of 2021, when Trump would become a lame duck if he wins a second term. Republicans would be smart to roll up their sleeves, get through with a primary and get on with articulating policies about taxes, small government and practical leadership that will resonate with voters.

Trump does have election liabilities, but they aren’t named Walsh or Sanford. Those in Kansas and other states who really want to help the president should do everything in their power to dismantle the @realDonaldTrump Twitter account.