While some Democrats express anxiety about whether front-runners in the presidential primary are strong enough to beat President Trump, mid- and lower-tier candidates are renewing their pitches for why they are the best pick to be the party’s nominee in 2020.

Democratic donors reportedly wonder whether it is too late for well-known figures such as Hillary Clinton, Michael Bloomberg, or Eric Holder to enter the race. They worry about Joe Biden’s tendency to ramble during speeches and his lackluster fundraising. Bernie Sanders, 78, had a heart attack in early October, raising concerns about his health. Elizabeth Warren, like Sanders, energizes liberals but may alienate moderate swing-state voters.

“To those Democrats who are looking for an alternative right now, I want to make the case today very directly: Look no further," New Jersey Sen. Cory Booker said at the National Press Club on Wednesday.

For many Democrats in the race, the path to victory rests on capturing voters looking for an electable candidate who is not as far left as Warren or Sanders.

"I'm getting calls from people, Biden supporters, who want to hedge their bet," Booker said.

Once a rising star in the Democratic Party, first as mayor of Newark and then elected to the Senate in 2013, Booker now finds his campaign cash-strapped and rarely breaking 3% in primary polls. He hopes his call to “rise” above negative, Trumpcentric messaging and his plan to energize minority voters will be his ticket to the White House.

"Democrats don't need more candidates to enter this primary," Booker said. "We have great candidates already."

Montana Gov. Steve Bullock made his main selling point when asked about Democrats looking for an alternative to the top tier: He is the only candidate who’s won a Trump state.

“He took Montana by 20. I won by four. A quarter of my voters voted for Donald Trump,” Bullock said in a CNN interview on Wednesday.

Bullock appeared in a July debate but is unlikely to make the cut for future debates. He entered the race in mid-May, later than most other candidates, and has spent less time on the campaign trail due to his gubernatorial responsibilities.

“I hope those party bosses — because they're not the ones that actually decide this or the debate rules — that they'll start looking at a guy from Montana that's won in the sort of places that we need to win and have been able to actually bring people together and get things done,” Bullock said.

Former Maryland Rep. John Delaney has been running for president longer than any other candidate in the large Democratic primary field and announced his candidacy in 2017.

“I can understand why many are worried about the vulnerabilities of the current top tier candidates. That's why it is so short-sighted of the DNC to try to narrow the field so far in advance of when the first votes are actually cast,” Delaney told the Washington Examiner.

Delaney is a multimillionaire who made his fortune founding finance companies and almost entirely funds his presidential runs with personal loans to his campaign. He made headlines when he was booed by California Democrats for opposing to a government-financed “Medicare for all” healthcare system and when he initiated heated exchanges with Warren and Sanders on healthcare during a July debate.

“Trump is going to run on the economy. To beat him we need a candidate who can go toe-to-toe with him on the economy and capture the center; I'm the best candidate to do that,” Delaney said.

Former Housing Secretary Julián Castro on Monday said he will end his presidential bid if he does not raise $800,000 by the end of the month, stressing that he is the only Latino candidate in the race making what might be his last pitch to voters and donors. He stressed that those at the top of the polls right now may not be the candidates voters prefer when voters go to the polls in a few months.

"What’s very encouraging to me is that even now with three months left until the end of the Iowa caucus, you have a lot of people who haven’t made up their mind and a lot of people who’ve expressed a preference for a candidate who say they could change their mind," Castro said on MSNBC Tuesday. "It’s still wide open, and I’m going to keep working hard to articulate a strong, positive vision for the country why I’m the right person to take on Donald Trump."