“As Nebraska’s attorney general, I’m leading the fight to overturn Obamacare," Bruning says in the ad. "Bob Kerrey says Obamacare doesn’t go far enough.”

Bruning ends the 30-second spot by calling the defeat of Kerrey and President Obama "the right choice for our future."

Stenberg, who is running behind Bruning in the primary but ahead of state Sen. Deb FischerDebra (Deb) Strobel FischerErnst, Fischer to square off for leadership post McConnell will ask Cornyn to stay on GOP leadership team Graham downplays need for bill reining in Trump on tariffs after White House meeting MORE (R), knocks Bruning as a big spender who would bring politics as usual to the Senate if elected. Stenberg is running with the support of prominent fiscal conservatives, including Sen. Jim DeMint (R-S.C.), the Club for Growth and various Tea Party groups.

"Making good decisions isn't hard. You just do the right thing," Stenberg says. "Jon Bruning seems to have a little trouble with that."

Stenberg contrasts the 13 percent by which he cut his treasurer's office budget by the 96 percent he claims Bruning upped the budget for his state office.

"We need a senator who will change Washington, not fit right in," Stenberg says.

The Republicans will square off in a May 15 primary. Kerrey is running unopposed for the Democratic nomination. The Hill rates this race as leaning Republican.

Watch Bruning's ad:

Watch Stenberg's ad: