By THOMAS BEAUMONT, Associated Press

OMAHA, Nebraska (AP) — Democrat Heath Mello lost his race for Omaha mayor Tuesday in a setback for supporters who argued that the Democratic National Committee and abortion rights groups were wrong to attack the anti-abortion former state senator.

Mello, a 37-year-old Catholic from Omaha's working-class south side, had become a flashpoint for the internal Democratic battle over whether a candidate's position on reproductive rights should disqualify him from support by the national party after its crushing losses around the country last year.

Tuesday, Mello acknowledged the "completely different dynamic" the campaign took on in the closing weeks, but noted what he described as unified support across ideological lines.

"We tried to run a campaign that was inclusive from the beginning regardless of political affiliation, regardless or ideology under the banner of change," Mello told hundreds in a west Omaha hotel ballroom.

Republican Jean Stothert, a 63-year-old former nurse and city council member elected in 2013, was elected to a second term.

It was another near miss for Democrats fighting to take back typically Republican territory. Last month, James Thompson lost a special election for a House seat in Kansas. In Georgia, Jon Ossoff narrowly missed an outright win in a special election.

The National Abortion and Reproductive Rights Action League slammed the Democratic National Committee for supporting Mello, who voted for abortion restrictions during his eight years in the Nebraska Legislature.

Responding to the criticism, Democratic party chair Tom Perez declared that, "every Democrat, like every American, should support a woman's right to make her own choices." His comment sparked a fierce debate within the party over whether there should be an abortion litmus test, with Mello caught in the middle.

"It's astounding that our party chairman would say pro-life Democrats are not welcome," Nebraska Democratic Party Chairwoman Jane Kleeb told The Associated Press Tuesday as Mello conceded.

A CBS News poll taken in January found 15 percent of Democrats nationally believed that abortion should not be permitted.

Omaha Democratic voter Adam Gouttierre, a 45-year-old business developer, said Democrats in Nebraska didn't have the luxury of being choosy. "Abortion is one item on the menu of progressive concepts," he said, frustrated at the backlash. "You can't have them all!"

At the April 20 rally in Omaha, Sen. Bernie Sanders, the Vermont independent who sought the Democratic presidential nomination last year, endorsed Mello, telling thousands, "Are you ready for a political revolution?"

Mello had cast himself as a next-generation Democrat focused on economic opportunity, while embracing GOP-friendly ideas such as public-private partnerships as a way to solve the city's vexing streets problem. "That's the future of the Democratic Party, in my mind, looking at that pro-growth, progressive, future-focused mentality."

A Mello win would have given Democrats a leg up in Nebraska's 2nd Congressional District, more than two-thirds of which is in Omaha, as the party hopes to claw its way back to the majority next year.

In thanking supporters, Mello hinted he was hardly finished by Tuesday's defeat.

"Our work does not stop tonight," he said. "It only begins."