The opening phase of the Republican presidential primary has largely centered on former President Donald Trump and Florida Gov. Ron DeSantis ′ escalating collision.

But a new wave of GOP White House hopefuls will begin entering the race as soon as next week following a months’-long lull. They include former Arkansas Gov. Asa Hutchinson, who will formally launch his campaign Wednesday.

Former Vice President Mike Pence has said he will finalize his plans in “weeks, not months.” He has kept a busy schedule of early state visits and policy speeches as aides have discussed details of an announcement including dates as early as May, but more likely in June. South Carolina Sen. Tim Scott, who has formed a presidential exploratory committee, is expected to join the race in a similar time frame.

Former New Jersey Gov. Chris Christie, meanwhile, has been meeting with former aides and returned to New Hampshire this week, where he told the first-in-the-nation primary state that, “Tonight is the beginning of the case against Donald Trump.” He has said he will make a decision “in the next couple of weeks.”

The contenders will enter the race at a critical moment as DeSantis, who hasn’t officially announced a campaign, has struggled to live up to sky-high expectations among some early backers. He has been losing support among elected Republicans in his own state to Trump and is prompting concern among some in the party that his positions on abortion and LGBTQ rights, among other issues, could render him unelectable in a general election. Trump in recent weeks has solidified his status as the race’s early frontrunner, even after he was indicted in New York, but remains the subject of intensifying investigations in Atlanta and Washington and persistent concerns about his electability after losing to President Joe Biden in 2020.

Would-be rivals hope that dynamic leaves an opening for one of the fresh entrants to emerge as an alternative to the current polling leaders. Some strategists hope Trump and DeSantis will attack one another so viciously that they will turn off voters, leaving them searching for an alternative.

“It’s not uncommon for a third candidate who’s not involved in the kerfuffle to rise,” said Bryan Lanza, a former Trump adviser, who has been informally advising Larry Elder, the conservative talk radio host who launch a his long-shot campaign Thursday.

Lanza said he expects a robust race to be the “leader of the second tier” of candidates currently polling at under 10%.

Beyond Trump and Elder, the current field of official GOP presidential candidates includes former United Nations Ambassador Nikki Haley and tech entrepreneur Vivek Ramaswamy, both of whom announced their bids in February.

President Joe Biden, meanwhile, is expected to announce his reelection effort as soon as next week. He faces minimal primary competition.

Among Republicans, the early debates that are slated to begin this summer could be crucial in determining who builds momentum, particularly given DeSantis’ expectations.

That means candidates may need to cement their planning soon, even if they’d prefer to wait longer. The Republican National Committee has scheduled the first debate for August and is expected to set strict benchmarks that candidates must satisfy to participate, including amassing tens of thousands of individual donors.

“That takes a little time to do and so if you’re gong to be serious about this — and I think you have to be on the stage to be serious about it — then you probably have to make the decision by May,” Christie said this week during an interview with the media outlet Semafor.

In the meantime, candidates-in-waiting have seen little reason to jump in sooner, particularly given Trump’s propensity to attack. Instead, they have been biding their time, visiting early voting states, delivering speeches and wooing donors as they assess the field. Pence, for instance, was in California this week meeting with potential backers and will host another donor retreat for his nonprofit group in late May.

“If I was in their shoes, I would wait as long as possible,” said former Wisconsin Gov. Scott Walker, who was considered an early favorite for the Republican nomination when he ran against Trump in 2016. He remembers realizing, in those early weeks, how dramatically Trump had upended the race, dominating everything.

“There was no way around it then,” he said. “And right now, anybody who thinks they’re somehow going to go in and change that is missing the reality.”

The rivalry between Trump and DeSantis has been turning uglier by the day, with political groups supporting both men already spending millions on attack ads.

While DeSantis has largely ignored Trump’s jabs questioning his commitment to Social Security, his relationship with young girls as a teacher decades ago and even his sexuality, a pro-DeSantis super PAC, Never Back Down, began to respond in its first round of paid ads last weekend.

“Trump should fight Democrats, not lie about Gov. DeSantis,” the narrator says in an ad that ran on Fox News. “What happened to Donald Trump?”

The spot ran in conjunction with an online attack ad that described Trump as “a coward” and a “gun grabber” geotargeted to attendees at an RNC donor retreat in Indiana.

Trump’s super PAC, MAGA Inc., meanwhile, has been airing its own trio of spots on cable news channels highlighting DeSantis’ votes to cut Social Security and Medicare and raise the retirement age.

“The more you learn about DeSantis, the more you see he doesn’t share our values. He’s just not ready to be president,” said the narrator in one. Another seized on a report that DeSantis once ate pudding with his fingers, urging DeSantis “to keep his pudding fingers off our money.”

Trump and his campaign have long seen DeSantis as his only serious challenger and believed the more crowded the field, the better for Trump, as candidates split the anti-Trump vote. But a repeat of 2016′s massive field hasn’t materialized, with potential candidates like former Secretary of State Mike Pompeo and former Maryland Gov. Larry Hogan passing on campaigns.

There are still plenty of unknown dynamics, including whether governors such as Kristi Noem of South Dakota or Chris Sununu of New Hampshire will launch campaigns. Both Texas Sen. Ted Cruz and Virginia Gov. Glen Youngkin have said they are focused on other races, but neither has explicitly ruled out a run, leaving open the possibility they could mount late-entry bids.

Mike DuHaime, a Republican strategist and longtime Christie adviser, believes that Trump is the favorite but nonetheless beatable. He cautioned that races are complicated, with unexpected outcomes.

“I do think that DeSantis is right now firmly the alternative to Trump, but I don’t know if it stays that way. There’s still way too long to go,” he said, arguing that a debate moment or news story could change the trajectory.

“Somebody’s just got to get momentum,” he said. “It’s just so wide open even with Trump being the prohibitive favorite.”