Story highlights Barletta was a supporter of Trump

He will try to unseat Sen. Bob Casey, a Democrat

Washington (CNN) Republican Rep. Lou Barletta of Pennsylvania announced a Senate campaign on Tuesday, challenging Democratic Sen. Bob Casey.

In a campaign video published Tuesday morning, Barletta, who was an early backer of Donald Trump during his presidential campaign, said he will challenge Casey to make "Pennsylvania and America great again."

In the video, Barletta said he himself "wasn't born with a famous last name" -- a reference to Casey, whose father served as Pennsylvania governor.

Still, Barletta enters the race as the best-known Republican in the primary field. Already, state Reps. Rick Saccone and Jim Christiana are running, as well as real estate executive Jeff Bartos.

Bartos has signaled he'll aggressively fight Barletta, airing a television spot knocking both Barletta and Casey by showing their pictures as a narrator says: "Career politicians make big promises but fail to deliver."

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