SALEM — John Frohnmayer, saying that campaign dollars and grassroots support never materialized for him, announced Tuesday he is dropping his long-shot bid for the U.S. Senate.

Frohnmayer had planned to run as the Independent Party’s candidate in a race pitting him against Republican Sen. Gordon Smith and Democrat Jeff Merkley.

But Frohnmayer said Tuesday that in recent days he had an “epiphany” in which he realized that “running for office just isn’t who I am” and that he was gaining little traction with voters.

“What I was looking for, in terms of a third-party race, was a kind of grassroots excitement, and I didn’t see that,” said Frohnmayer, the brother of University of Oregon President Dave Frohnmayer.

Most observers believed that Frohnmayer had faced tall odds in trying to compete with Smith and Merkley, who both are expected spend millions of dollars on TV ads in the fall campaign.

There had been speculation that Frohnmayer’s candidacy might draw more votes from Merkley than Smith, since Frohnmayer was trying to appeal to progressive voters with his calls for universal health care and public financing of congressional races.

The Independent Party could still nominate someone else to run for the U.S. Senate. But party spokesman Sal Peralta called that unlikely and said the party is going to focus instead on finding candidates to run in uncontested legislative races around the state.