It’s here: There are 35 days until Election Day, but voting has begun in Pennsylvania.

Mail ballots are being printed and sent to the more than two million voters who have already requested them, and counties are beginning to allow a type of early voting at local elections offices. Some are opening satellite offices as early voting sites.

In a state seen as increasingly pivotal in deciding the winner, the start of voting crosses a new threshold in the campaign, as people finally begin to formally weigh in on what has been seen as a day of reckoning ever since the 2016 campaign ended.

“We are gearing up for a very exciting week,” Philadelphia elections chief Lisa Deeley said last weekend. The city’s first 100,000 ballots were being mailed Monday, with 180,000 more to follow in batches over the next few days. And its first satellite elections offices will open Tuesday to allow people to vote early by requesting, receiving, completing, and submitting mail ballots in one trip.

The fevered presidential campaign has drawn historic levels of interest, with both parties painting it as an existential choice about the country’s future. People are voting as polls consistently show Democratic nominee Joe Biden holding a strong lead nationally, and a smaller but steady edge in Pennsylvania, one of a handful of states likely to decide the outcome of the contest between him and President Donald Trump.

Polls also show a remarkably stable race despite a year of historic upheaval — though another set of events and revelations looms as voting starts, and after 2016, no one is counting anything out. Trump and Biden will have their first debate Tuesday night. The Senate is about to embark on a charged confirmation battle over Trump’s Supreme Court nominee Amy Coney Barrett. And the New York Times on Sunday revealed long-hidden details of the president’s tax returns, including that he paid just $750 in federal income tax the year he was elected, mostly because his vaunted businesses have lost piles of money.

The candidates will continue their frequent travels to Pennsylvania this week, after Trump staged two rallies last week, just outside Pittsburgh and Harrisburg. Vice President Mike Pence will be in Lancaster County for a debate watch party on Tuesday, and Biden will stop in Johnstown on Wednesday as part of a train tour through Ohio and Pennsylvania.

Democrats have so far been far more eager to vote by mail, requesting 1.5 million ballots to date, compared with 535,000 from Republicans and 223,000 from people who are independent or registered with a third party, according to data from the Pennsylvania Department of State. That gap, driven by Trump’s false attacks against mail voting, gives Biden a greater chance to lock in support now, ahead of Election Day, when personal emergencies, long waits, or the coronavirus could deter some voters.

But it also carries risks, since casting mail ballots requires following a sometimes confusing set of rules, creating tripwires that make mail votes far more likely to be rejected than those cast in person. A raft of litigation and legislative wrangling has left the very rules of mail voting up in the air, adding to uncertainty about how such votes will be counted — and increasing the likelihood that the results won’t be known for days after voters go to the polls.

The timeline for sending out ballots is slightly different in each of the state’s 67 counties — some have already begun mailing them and opening early voting offices, others are still finalizing things — but officials expect to mail hundreds of thousands of ballots this week.

Allegheny County started sending ballots Wednesday, and as of Monday had mailed about 106,000. More than 90,000 Delaware County ballots began printing this weekend, and will be mailed out by the end of the week. Montgomery County’s first ballots go out Wednesday. Chester County’s first ballots began going out at the end of last week — some voters have begun receiving them — and the rest of them will be sent out by midweek.

“There are going to be a lot of votes cast this week, so it’s a big week,” said Michael Pipe, chair of the Centre County commissioners. The county is mailing ballots Wednesday to the more than 27,000 voters who have requested them so far, and Pipe expects most of those voters to receive their ballots by next Monday.

This is the first year all Pennsylvania voters can vote by mail, if they choose, thanks to a law passed last year, and the pandemic has fueled massive demand for mail ballots. In the primary, just over half of all votes were cast by mail. The Pennsylvania Department of State, which runs elections, estimates that about three million votes will be by mail this election.

Both parties have tried to encourage mail voting. Campaigns like knowing their supporters have already voted, and that their candidates won’t lose votes because of Election Day mishaps, like a flat tire, illness, or simple forgetfulness.

But Trump has repeatedly disparaged the method, falsely claiming it is rife with fraud and citing mail ballots as the reason he may not accept the results of the election if he loses. Many GOP voters have followed his lead, despite national, state, and county Republican organizations encouraging mail voting.

Voters have been waiting to receive their ballots for months, with rising levels of anxiety visible on social media posts and in emails to reporters.

Elections officials had hoped to send them in mid-September, but that was held up by a Democratic challenge to the Green Party presidential ticket. When the state Supreme Court removed the party’s ticket from the ballot on Sept. 17, it cleared the way for ballots to be finalized and mailed. Counties rushed to update their ballots so they could be printed.

The court’s rulings that day also extended the deadline for when completed ballots can be returned and mandated that “naked ballots” mailed without an inner secrecy envelope be thrown out. That further delayed the process as counties updated instructions and envelopes. It was too late for some: Philadelphia’s ballot instructions have been updated, but they’ll be delivered in envelopes that declare, wrongly, “You must return your ballot to your county election office by 8 p.m. on election day.” The court ruled they could be accepted through the Friday after the Nov. 3 Election Day.

Some voters will have to wait a little longer.

“We’re doing them in batches, in waves,” said Lebanon County elections director Michael Anderson. “They’re going to get there.”

Because they’re being sent out in batches — and because mail delivery times can vary — people may receive their ballots on different days, even if they live at the same address and applied at the same time. For example, Lebanon County’s first ballots are being sent to voters who are not registered as Democrats or Republicans.

“You may have somebody where one person in the household gets one and another didn’t,” Anderson said.

And Allegheny County has so many ballots to mail — almost 325,000 so far — that it could take two weeks before they are all sent to voters.

Voters can use the Department of State’s online ballot tracker to see whether their ballots have been mailed, though the data sometimes contain mistakes. Voters who include email addresses when requesting mail ballots should receive notification emails when those ballots are being mailed out.

The hundreds of thousands of ballots crisscrossing the state this week also signal another change: The start of “early voting.”

While Pennsylvania does not have traditional early voting, the law expanding mail voting also required counties to allow voters to receive mail ballots on demand at county elections offices. That means voters who visit their county office can request, receive, fill out, and submit a mail ballot on the spot. (Every county has a different timeline for when it will allow early voting, so contact your elections office to check.)

Some of the state’s largest counties are also planning to open satellite elections offices to make early voting more accessible.

“The excitement among voters to make their voice heard this fall is high,” said Deeley, the chair of the Philadelphia city commissioners, who run elections. “And we are equally excited to be able to provide them with safe and convenient ways to do that.”