Please note: The Washington Post is providing this important election information free to all readers. Get election results and other major news delivered to your inbox by signing up for breaking news email alerts.

President Trump’s reelection campaign said Wednesday that it would launch a legal blitz to try to halt vote-counting in Pennsylvania and Michigan, would seek a recount in Wisconsin and challenged the handling of ballots in Georgia, threatening to draw out the final results of the razor-thin White House contest.

The campaign’s aggressive legal posture while the presidential race remains unresolved underscored how the close margins in key states have raised the stakes for litigation over which ballots will count. It comes after Trump, who has repeatedly made unsubstantiated claims of fraud in the election, pledged to get the courts to determine its outcome.

Democrats said they were unfazed by what they said was legal posturing by the president’s campaign. They said they were well-prepared to fend off any lawsuits or appeals.

“We’re winning the election, we’ve won the election, and we’re going to defend that election,” Bob Bauer, a top attorney for the Biden campaign, said Wednesday morning in a call with reporters. “So we don’t have to do anything but protect the rights of voters and to stand up for the democratic process.”

By Wednesday afternoon, Edison Research projected Biden the winner of Wisconsin and Michigan. In Pennsylvania, Trump held a narrow lead with an estimated 1 million ballots still left to count. In Georgia, Biden was trailing Trump by fewer than 48,000 votes shortly before 8 p.m.

In a series of rapid-fire announcements throughout the day, Trump campaign officials said they planned to ask courts to halt vote-counting until more access is granted for Republican observers in Michigan and Pennsylvania; seek to initiate a recount in Wisconsin; and intervene in litigation pending before the Supreme Court over Pennsylvania’s extended deadline for mail ballots.

The campaign also said it would challenge guidance related to voter identification rules for some voters in Pennsylvania, one of a half-dozen legal efforts undertaken by Republicans in the state this week. And in Georgia, the campaign sued election officials in Chatham County, home of Savannah, alleging that ballots arriving after the 7 p.m. deadline may have been mixed in with eligible ballots and improperly counted.

“With these key actions, President Trump is telling all Americans he will do whatever it takes to ensure the integrity of this election for the good of the ­nation,” deputy campaign manager Justin Clark said in a statement.

Trump said early Wednesday that he wants the Supreme Court to determine which ballots should count, falsely claiming victory while millions of votes were still outstanding.

“Frankly, we did win this election,” the president told supporters overnight at the White House. “We did win this election. So our goal now is to ensure the integrity for the good of this nation. This is a very big moment. This is a major fraud in our nation. We want the law to be used in a proper manner. So we’ll be going to the U.S. Supreme Court.”

Legal experts noted that Trump cannot simply seek the Supreme Court’s intervention in the election and stop the counting of ballots.

There is no routine review of election results at the high court, and its most consequential election case — Bush v. Gore, which effectively determined the outcome of the 2000 presidential race — did not arrive there for about a month.

The court’s power is constrained, and justices can entertain only specific constitutional questions that have risen from lower courts or where they have original jurisdiction. A direct appeal from the president to intervene in an election does not count under these rules.

“You can’t bring a case directly to the Supreme Court in an election dispute. . . . And there’s no legal cause of action that says, ‘Stop the count and declare me the winner,’ ” said Joshua A. Douglas, a professor at the University of Kentucky’s Rosenberg College of Law.

Bauer said that if Trump at some point sought to go before the court to try to stop the counting of ballots that were lawfully cast, “he will be in for one of the most embarrassing defeats the president ever suffered before the highest court of the land.”

Leaders in battleground states defended their elections as well-run and refused to halt the vote counts.

In Pennsylvania, Democratic Gov. Tom Wolf called the GOP effort an attempt “to subvert the democratic process.”

“Pennsylvania will fight every attempt to undermine the election,” he said. “We will count every vote.”

In Wisconsin, Elections Commission Administrator Meagan Wolfe rejected the idea that there have been irregularities in the state’s count, telling reporters that the election “proceeded in a very normal fashion.”

Wisconsin officials said all of the state’s 1,850 local clerks completed an initial count of in-person and absentee ballots Wednesday and had started conducting local canvassing of results to double-check their findings.

Wolfe’s comments to reporters came after Trump campaign manager Bill Stepien said in a statement that the campaign would request an immediate recount of the vote in Wisconsin, citing “reports of irregularities in several Wisconsin counties which raise serious doubts about the validity of the results.”

Wolfe said the counting had gone exceptionally smoothly and that to suggest otherwise was an “insult” to election workers who had prepared carefully for the day. She noted that the counting process was open to the public from start to finish and that some localities even live-streamed images of their absentee ballot-counting.

“There are no dark corners or locked doors in elections,” she said. “Anyone was free to watch.”

In Michigan, Democrats said the lawsuit the Trump campaign filed seeking to halt vote-counting was preposterous — calling it a stunt designed to promote a false White House narrative of fraud in the counting of mail ballots.

“My understanding is counting of ballots across the state is nearly complete,” said Christopher Trebilcock, an election law specialist representing Democrats in the state. “If they want to challenge the results of the election after all legal votes are cast, Michigan law has a process for that after the canvass is complete.”

While the Trump campaign went to court in the state, a vocal group of would-be Republican Party election challengers gathered Wednesday afternoon at the TCF Center, a Detroit convention center where votes were being counted. Election challengers are people who monitor vote-counting on behalf of parties or candidates.

After officials capped the number who could go because of the coronavirus pandemic, a group of would-be observers demonstrated loudly outside, chanting, “Stop the count.”

Whether any case ends up before the Supreme Court remains to be seen. The most obvious path for a review by the justices would be a specific challenge to ballots in a closely divided state that could tip the results of the election.

The Supreme Court’s work typically comes after a ruling in a case by a local judge that has gone through the appellate process. In Bush v. Gore, the court was reviewing decisions of the Florida Supreme Court, for instance, and issued its opinion Dec. 12, with the deadline for naming members of the electoral college looming.

Extended deadlines for returning mail ballots in many states were already hotly contested in litigation before Election Day. But some key cases were not heard by the Supreme Court, which could agree to hear appeals in some of those suits — now with a new conservative justice, Amy Coney Barrett, on the bench.

In Pennsylvania, the state Supreme Court allowed mail ballots postmarked by Election Day to count if they arrive by the end of the day on Nov. 6, delivering a win for voting rights advocates and Democrats who argued that voters deserved more time because of the pandemic and delays in the mail.

Republicans twice sought help from the U.S. Supreme Court and were rebuffed, but Justices Clarence Thomas, Samuel A. Alito Jr. and Neil M. Gorsuch suggested they are open to revisiting the case after the election.

“There is a strong likelihood that the State Supreme Court decision violates the Federal Constitution,” Alito wrote.

The three justices said the commonwealth should segregate those ballots that are delivered after Election Day in case of further legal action, and state officials agreed.

The Trump campaign filed a brief Wednesday afternoon seeking to intervene in that case.

“Given last night’s results, the vote in Pennsylvania may well determine the next President of the United States,” wrote Trump lawyer Jay Sekulow. “And this Court, not the Pennsylvania Supreme Court, should have the final say on the relevant and dispositive legal questions.”

The Supreme Court requested a response from Pennsylvania Democrats to that motion by 5 p.m. Thursday.

A Democratic lawyer who spoke on the condition of anonymity to discuss the Biden team’s legal strategy in Pennsylvania said the campaign believes the best thing it can do is stay out of the way of election officials as they work through the count.

The Biden team believes it has a strong argument under a legal principle known as the reliance interest, which protects voters relying on instructions they received on how to vote legally, the lawyer said.

“The Supreme Court really cares about the reliance interest,” the lawyer said. “You could see them saying, ‘Yes, we believe that the state courts overstepped their bounds here, but we are not going to throw out ballots that voters believed at the time were lawfully cast.’ ”

Whether the Supreme Court plays a role in post-election legal fights could depend on how close the results are.

Douglas, the University of Kentucky law professor, said the question of who has authority to extend a state’s mail ballot deadline is “certainly a live legal issue” but that he does not expect the issue to rise to the Supreme Court during this election unless the vote margins are extremely narrow.

And even then, four justices would have to agree to take a case that would risk further politicizing the court. Alito, Thomas and Gorsuch might agree, Douglas said, but it’s unclear whether Chief Justice John G. Roberts Jr. or Justice Brett M. Kavanaugh would want to — “and we have no idea about Barrett.”

“I don’t think resolving Trump v. Biden is something the justices want to do,” Douglas said. “I think certainly Chief Justice Roberts is very concerned about the institutional legitimacy of the court. I don’t think it’s the sort of things he wants the court to resolve.”

Aziz Huq, a constitutional law professor at the University of Chicago, said he thinks it is “unlikely that there will be a dispute about ballot-counting that will reach the Supreme Court.”

He pointed out that if Wisconsin turns out to be a tipping-point state, Republicans have already brought litigation about its ballot deadline to the Supreme Court and won. The court declined in late October to extend the receipt deadline past Election Day.

Republicans’ legal efforts Wednesday came after party members filed several lawsuits in Pennsylvania on Election Day.

In the first case, a GOP congressional candidate filed a federal lawsuit against authorities in Montgomery County seeking to toss out mail ballots with errors that were fixed by voters before Election Day. A second Republican lawsuit in state court claims that Pennsylvania Secretary of State Kathy Boockvar (D) broke the law by advising county officials Monday to help voters resolve errors discovered on their ballots.

The Democratic National Committee has intervened in both cases, arguing that the Republican candidate lacked standing to bring her lawsuit and did not demonstrate “future irreparable harm,” and that Democratic candidates could be harmed by the statewide case.

In a third lawsuit filed Tuesday, the Trump campaign accused Bucks County election officials of inappropriately disclosing the identities of voters with defective ballots to party observers seeking to help them correct the errors. A judge rejected the petition; the campaign did not respond to a question about whether it plans to appeal.

And in yet another case, the Trump campaign appealed a court’s rejection of its request to be able to observe ballot-counting in Philadelphia more closely.

A judge ruled Tuesday that Trump’s observers were given enough access and that county officials were not required to allow them to “observe the writing on the outside of the ballots.”

The Trump campaign filed a notice Wednesday that it would challenge the decision in Commonwealth Court but did not immediately set out its arguments.

Nevada, where Biden clung to a tiny margin Wednesday, has already seen a slew of last-minute GOP lawsuits challenging the counting process.

The state Supreme Court on Tuesday night unanimously rejected a request from the Nevada Republican Party and the Trump campaign to halt the counting of some mail ballots in Clark County, a Democratic stronghold where votes for Biden would be key to his potential victory.

As a result, Clark County will be able to continue counting most mail ballots under its current protocol. County officials must count any mail ballots postmarked by Election Day that arrive by Nov. 10, and they must complete their canvass by Nov. 16.

As of Wednesday evening, Biden held a narrow lead of fewer than 8,000 votes in Nevada, but there were many mail and provisional ballots left to count, including mail ballots postmarked by Election Day but received afterward.

In an interview Tuesday, Gov. Steve Sisolak (D) said the legal tactics were an effort by Republicans to undercut the Democratic advantage.

“They’re knocking on courthouse doors, and we’re knocking on Nevada doors,” Sisolak said. “I have confidence that the court system is going to see these for what they are.”

Jon Swaine, Michelle Ye Hee Lee, Amy Gardner, Josh Dawsey, Emma Brown, Matt Viser and Aaron Schaffer in Washington, Kayla Ruble in Detroit and Ryan Slattery in Las Vegas contributed to this report.