Kentucky Lt. Gov. Daniel Mongiardo has an 18-point lead over Jack Conway in the state's Democratic Senate primary, according to a poll for Mongiardo's campaign.

The Garin-Hart-Yang poll has Mongiardo at 43 percent and Conway at 25 percent. Nearly 30 percent of voters are undecided, however, and the polling memo notes that Conway has a significant cash advantage heading into the final three months of the campaign.

Mongiardo has shown a lead in most polling of the primary, but his lead in the latest is one of his biggest. Mongiardo's campaign released a poll in May of last year showing a 15-point lead.