Updated 1:39 p.m. | Cincinnati City Councilman P.G. Sittenfeld declared Thursday he would stay in the Ohio Democratic Senate primary, despite efforts by supporters of former Democratic Gov. Ted Strickland to convince him to drop out.

“I have come here today to affirm my candidacy and to explain my campaign,” Sittenfeld said Thursday morning, according to prepared remarks.

Sittenfeld, 30, and Strickland, 73, are vying to challenge Republican Sen. Rob Portman. Strickland, who served four nonconsecutive terms in Congress and one term as governor, is regarded by Democrats as the overwhelming front-runner for the nomination.

And while Strickland supporters are adamant the younger Sittenfeld poses no threat to Strickland’s ambitions, pressure has grown for Sittenfeld to exit the race.

“When you have a primary with great candidates running, you drain all your resources and you don’t have enough resources for a real race, which is the general,” Democratic Rep. Joyce Beatty, who endorsed Strickland, told CQ Roll Call recently. “So I would be hopeful that we could figure out a way to have a team where there is a place for everyone in the race.”

Part of the frustration, Ohio Democrats said, stems from the fact that every minute spent discussing or focused on a Democratic primary is a moment when Portman is able to run and raise money with no opposition.

“There’s a general sense of, you know, Rob Portman is the one we’re trying to beat here, why are we having this discussion,” Rep. Tim Ryan, another Strickland backer, told CQ Roll Call recently.

Plus, some Strickland backers feel the very basis for Sittenfeld’s candidacy — that he would provide “the kind of new leadership that will make this campaign an exciting conversation about the future, rather than a stale argument about the past,” as he said in Thursday’s speech — is a direct attack on Strickland and his age.

Until recently, the two Democrats had shied away from attacking each other directly. But the gloves came off in Sittenfeld’s Thursday speech, and though he only mentioned Strickland by name once, the speech read like a litany of reasons Strickland was too old to be the nominee.

“At base, it is a contest between change and the status quo, between the old and the new, between the future and the past,” Sittenfeld said.

Strickland has used the age differential to his own advantage, too. Sittenfeld, at 30, is just old enough to legally run for Senate.

“This is not a Little League Baseball game. This is a U.S. Senate race,” Strickland told the Ohio Democratic Party executive committee last month.

A number of Democrats said Sittenfeld, who entered the race first, originally told them he planned to drop out if Strickland got in, and Ohio Democrats fully believed he would do so. But when Strickland announced, Sittenfeld showed no inclination to exit the race.

“A lot of people are disappointed cause it feels like he lied to them,” Ryan said.

So Strickland’s team rolled out endorsement after endorsement — from the entire Ohio congressional delegation, the Democratic Senatorial Campaign Committee, even one from former President Bill Clinton, designed to illustrate that Strickland is who likely 2016 Democratic presidential nominee Hillary Clinton wants on the ticket with her in the crucial swing state.

Last month, the Ohio Democratic Party voted to make an unusually early endorsement of Strickland.

But Sittenfeld raised more than Strickland in the first quarter, giving him little incentive to drop out. And the frequent barbs in the councilman’s speech suggest it could be a nastier primary than anticipated.

“I see a future in which senators care more about A+ ratings for schools than about A+ ratings from the NRA,” Sittenfeld said, a backhanded attack on Strickland who once sported such a rating from the NRA.

Strickland’s record as governor, Sittenfeld said, would also be a liability.

“Senator Portman wants to make this election about the past — which is why he and his allies are already attacking Ted Strickland’s record as governor,” Sittenfeld said. “But he can’t play that game with me.”

If such attacks continue, it could be hard for Strickland to ignore Sittenfeld and run as the presumptive nominee.

DSCC Communications Director Justin Barasky brushed off Sittenfeld’s speech, saying he had not yet watched it.

“Rob Portman is attacking Ted Strickland because he knows Strickland can beat him. … Portman ignores Sittenfeld for the same reason Roll Call should and that’s the simple fact that PG isn’t going to be the Democratic nominee,” he said.

A spokesman for Strickland did not immediately respond to CQ Roll Call’s request for comment.

The race is rated Leans Republican by the Rothenberg & Gonzales Political Report/Roll Call.

Clarification: This post has been updated to clarify the Ohio Democratic Party’s bylaws for endorsing candidates in primaries.

Related:

Democrats Skeptical Ted Strickland Will Face Primary

Several Ohio Democrats Considering Senate Primary

How Republicans Could Risk a Senate Seat to Win the White House

The 7 Most Interesting First-Quarter Fundraising Facts

Sticking Around Could Make Portman Senate’s GOP MVP

Roll Call Race Ratings Map: Ratings for Every House and Senate Race in 2016

Get breaking news alerts and more from Roll Call in your inbox or on your iPhone.