There's a little more than two weeks before May primary ballots go out, and the contest for Portland mayor remains wide open.

The most competitive mayoral primary in 20 years comes down to this: All three major candidates are sitting on enough money to reach voters with television advertising.

Candidates often stumble into the final weeks depleted of money on hand. That can be a big problem for getting your name out there—TV stations require cash up front from candidates to buy air time.

"TV is still the No. 1 way in which people get information about politics," says Jim Moore, political science professor at Pacific University. "It has surpassed newspapers, and social media is not anywhere close."

Airing TV ads was crucial in now-U.S. Rep. Suzanne Bonamici's victory in the recent 1st Congressional District special election. She spent virtually all of her money on TV and went on the air ahead of opponents.

The mayoral candidates have absorbed that lesson to varying degrees. Brady, for instance, has spent $565,000 without buying air time, but she hasn't moved the needle with voters.

Neither has Hales, who has spent a lot less. A Hales poll conducted in late March shows him at 25 percent and Brady at 23. A September 2011 poll showed both in the same range.

Brady released her TV ads this week, followed by Hales. Brady's emphasize her biography and jobs. Hales' ads focus on issues such as potholes, sewer rates and schools.

Smith hasn't released any ads yet. He has invested resources mainly in canvassing and blanketing the east side with blue-and-orange lawn signs. He's also a bit of a wild card. As Bus Project director, he oversaw guerrilla marketing campaigns to reach voters in unconventional ways.

"No candidate is grabbing the attention of voters," Moore says. "If you want to win, you've got to do something about that."

Follow the candidates' cash balances every day on our Campaign Finance page.