Douglas, who is seeking the GOP nomination in next Tuesday's primary, is running the ad in the Baltimore cable market, his campaign said. The ad, titled "Cardin-omics," plays off a recent television spot aired by Cardin.
It is the first television ad in the Republican primary.
"Cardin votes against the Keystone pipeline, gas prices go up," the narrator says in the 30-second ad as words are written on a chalkboard and images of a classroom are shown. "Cardin votes for Obamacare, costs skyrocket…After 45 years, it's time to retire Ben Cardin. Vote Richard Douglas for a better economy."
Many of the claims made in the ad, including that gas prices have increased because of the Obama administration's decision to delay the Keystone pipeline, are dubious. Most industry experts say building the pipeline could have an impact on prices -- a few cents per gallon -- but they also say the current spike in prices is being caused by far broader economic factors.
Health care costs, meanwhile, were skyrocketing before Congress passed the new national health care law in 2010. Most of the provisions of that law do not take effect until 2014.
Since Douglas is not facing Cardin in the primary election -- his two biggest challengers for the GOP nomination are Daniel John Bongino and Corrogan R. Vaughn -- the ad is intended to pivot voters to the general election and to signal that Douglas, if nominated, would run an aggressive campaign focused on Cardin's record.