Voters in Colorado primaries are seeing similar Democrat-funded ads ginning up Republican support for GOP candidates who seem easier to beat in the general.

As of March 31, Republican state Rep. Ron Hanks had raised $57,473 and had $16,165 cash on hand for his U.S. Senate campaign, while the frontrunner, Republican businessman Joe O’Dea, had raised $1,451,498. Concerned that Mr. O’Dea could give Sen. Michael Bennet a real fight, Democrats are spending as much as $3.5 million attacking Mr. Hanks as—you guessed it—“too conservative for Colorado.”

The ads accuse Mr. Hanks of wanting to ban all abortions, build a border wall, and expand gun rights. Mr. O’Dea’s campaign suspects Democrats are also behind mailers painting Mr. O’Dea as a liberal and in favor of gun control—with no mention of his endorsement by the state’s chapter of the National Rifle Association. (The mailers illegally fail to disclose their donor.) Knowing that President Biden won Colorado by more than 13 points, Democrats seem to think their best option is saddling the GOP with a candidate who can’t raise money and holds extreme views.