Brunner’s campaign said the Democratic attack betrayed McCaskill’s fear of a general-election contest against Brunner, whom a spokesman said had created more than 1,300 jobs while he was at the helm of Vi-Jon.

“It is truly despicable that Claire McCaskillClaire Conner McCaskillNail manufacturing exec who voted for Trump blames him for layoffs, asks Democrat for help The American economy is stronger than ever six months after tax cuts The Hill's Morning Report — Sponsored by PhRMA — Immigration drama grips Washington MORE and her allies on the far left are gleefully using tragic job losses of any kind as a tool of political partisanship, especially since they are responsible for the job-killing policies that are destroying the private sector economy,” said Brunner spokesman Todd Abrajano.

Abrajano said a total of 36 employees were laid off by the company in October 2011.

Brunner has made substantial gains in upping his name recognition in the four months since he entered the Senate race, but is still polling behind former state Treasurer Sarah Steelman and Rep. Todd Akin (Mo.) in the GOP primary.

Still, Brunner’s personal wealth could help him compete with McCaskill’s fundraising prowess: He donated slightly more than $1 million to his campaign in the last three months of 2011.

- This post was updated on Feb. 9, 2012 at 11:16 a.m.