Former Commerce Department official Ro KhannaRohit (Ro) KhannaOvernight Defense: Over 500 amendments proposed for defense bill | Measures address transgender troops, Yemen war | Trump taps acting VA chief as permanent secretary Lawmakers seek to limit US involvement in Yemen's civil war Freshman lawmakers introduce congressional term limits proposal MORE (D) knocks Rep. Mike Honda (D-Calif.) in his newest ad, the first time Khana has publicly gone negative against Honda in their race.

"First, Mike Honda stubbornly refused all debates. Now Honda's slinging mud, launching false attacks. Isn't it time to put the old politics aside?" the ad says, referencing a recent mail piece in which Khanna attacked Honda.

The spot then touts newspaper endorsements of Khanna, saying he's "for our future."

The well-funded Khanna is looking to make the runoff against Honda in the all-party June primary in the heavily Democratic district.