Tonight could be the start of days of suspense before we know who the next president will be. But it could also be effectively over by the end of the week — and there's a small chance we could even know tonight.Here are the three scenarios for election night and beyond, and how we'll know which one we're seeing tonight.1) The quick win: This one would only happen if Joe Biden scores a convincing win tonight in Florida — or possibly a surprise win in a big state like Texas or a combination of smaller states. If that happened, and the margins were clear enough that the states could actually be called for Biden, there would be effectively no path for President Trump to win 270 electoral votes.There's less likely to be any state that Trump could win early, at least under the latest polling trends, that would end Biden's path as effectively.2) Election Week: This is the scenario if there are enough battleground states that are so close they can't be called tonight — but might be called tomorrow, or possibly at the end of the week.Under this scenario, the historic avalanche of mail ballots could become more important — especially in a state like Pennsylvania, where we might not know the majority of results until at least Friday.But it's also possible that we'll know enough about the trends in big battleground states like Florida, Wisconsin and Michigan that we'd have a general idea where it's headed.Another scenario could be poll-defying election-night results that not only appear to show Trump holding the states he won in 2016, but also picking up one or more other small states.Even if it was too soon to call enough states to declare a win, it could shift the conversation around momentum and expectations.  3) Deadlock: This is the nightmare scenario — where it's so close in Pennsylvania or other states that lawsuits could bring everything to a halt.In this scenario, Trump campaign lawyers would likely challenge mail ballots arriving after Election Day and argue they shouldn’t be counted, Axios' Jonathan Swan reports. That could go all the way to the Supreme Court, where Trump’s allies like their chances given the court’s added conservative tilt following the confirmation of Amy Coney Barrett.They'd also fight any Democratic attempts to keep polls open longer today, and fight for access to review the counting of the ballots.Democratic lawyers are ready to respond to any GOP legal challenges, and they're also ready to sue to keep polls open, Axios' Stef Kight reports. Under this scenario, it could be weeks before we know the outcome.Go deeper:How the Supreme Court is handling election cases2020 election strategy: Hire all the lawyers