This could be the final time Hillary Clinton and Bernie Sanders go head-to-head in a debate.
The Democratic presidential candidates agreed in theory to another debate in May, but no real plans have been made yet. Clinton could easily decide to skip it if she continues on her current trajectory, which is expected to give her a virtual lock on the Democratic nomination after a round of primaries on April 26.
That adds to the pressure on both candidates when they take the stage at Brooklyn's Navy Yard Thursday night, but especially Sanders, who needs a win in Tuesday's New York primary to retain even a glimmer of a path to the Democratic nomination.
Clinton, known for her meticulous debate preparation, is huddling with aides at her home north of the city in Chappaqua ahead of the bout. Meanwhile, Sanders' Senate chief of staff, Michaeleen Crowell, took the train up from Washington to stand in as Clinton in final prep sessions before the main event in the senator's hotel.
Here are four things to watch for in Thursday night's high-stakes debate:
Tone wars - The slate of Democratic debates kicked off with an unusual moment of bonhomie between the leading candidates when Sanders gave Clinton a pass on her "damn emails" back in Las Vegas in October. The series will likely close on a much nastier note.
Thursday began with Sanders distancing himself from a speaker at his rally the night before who condemned "corporate Democratic whores" one sentence after hitting Clinton. And that was just the latest in a series of escalating attacks in both directions. Last week, Sanders called Clinton "unqualified" to be president. Clinton has suggested that if Sanders can't handle the pressure of the New York primary, he can't handle the general election.
Expect both candidates to take umbrage at the others' tone — even while replacing their own gloves with brass knuckles.
Donations - The skyline of lower Manhattan is visible from the debate site, and Sanders is likely to focus as much or more than ever on Clinton's donations from Wall Street, as well as her paid speeches. Major banks have been among Clinton's largest donors of her career.
In particular, Sanders may bring up the $225,000 Verizon paid Clinton for a speech in 2013. Both Clinton and Sanders joined picket lines of Verizon workers on Wednesday, who are striking over a labor dispute. The main labor union representing workers has endorsed Sanders.
Clinton's campaign says the attacks are baseless, but Clinton stumbled when pressed on Wall Street donations during a debate in Iowa earlier this year, awkwardly invoking the September 11 terror attacks. And Clinton has yet to find a satisfying answer as to why she won't release the transcripts of the paid speeches she delivered between her tenure at the State Department and presidential campaign launch.
Sanders will have fresh ammunition on this front with a new report out Thursday that five of the biggest banks failed to meet standards established under the Dodd-Frank Act for dismantling themselves during a financial crisis without a taxpayer bailout.
Devil in the details - Clinton and her campaign have been pounding Sanders as ill-equipped to go up against Donald Trump or Ted Cruz as the party's nominee and uninterested in key parts of the job of being president due to his alleged lack of depth on policy issues.
Clinton will likely respond to any attempts to tie her to Wall Street by citing Sanders' interview with theNew York Daily News editorial board, where he failed explain clearly his plan to break up the big banks. He also struggled in that interview with foreign policy, an issue Clinton surrogates highlighted Thursday. Clinton will likely contrast that meeting with her own, better-reviewed interview with the same paper.
Gun fight - Gun policy has been one of Clinton's most effective weapons against Sanders all year, allowing her to outflank the Vermonter on his left. But the issue is especially resonant in New York City, where gun crimes are an all-too-common fact of life.
She, too, will have fresh ammunition, in a Connecticut judge's decision to side with victims of the Sandy Hook shooting spree against gun manufacturers. Sanders opposes the lawsuit, as he reiterated in thatNew York Daily News interview, saying manufacturers should not be liable for gun deaths.
Bonus: Opposition-research bomb? — The former secretary of state tends to come prepared with a little tidbit of previously unused opposition research to try and catch Sanders off guard, which her camp keeps tightly under wraps. In New Hampshire, it was a vote Sanders took on a non-binding Senate resolution in favor of regime change. In Michigan, it was his vote against the auto industry bailout. The attacks sometimes unravel under scrutiny, but have a tendency to grab headlines or knock Sanders off balance. Will she have one Thursday? And will Sanders come with is own?
This article originally appeared on MSNBC.com.