A Democratic group is wading into the Republican Senate primary in Ohio with a new television spot aimed at promoting the conservative credentials of Bernie Moreno, a Cleveland-area businessman who has been endorsed by former President Donald J. Trump.
The spot criticizes Mr. Moreno as ultraconservative and too aligned with Mr. Trump. But by running the ad in the final week of the primary, those critiques are likely to be viewed as badges of honor by Republican primary voters, a tactic Democrats have employed in other races in recent years.
A group called Duty and Country is spending roughly $879,000 on the ad, which is set to run across the state, according to AdImpact, a firm that tracks advertising.
The group is funded largely through the Senate Majority PAC, the principal super PAC supporting Democratic efforts to maintain control of the chamber.