Joe Biden is a rule-follower running against a rule-breaker. So, while Donald Trump was busy announcing in the wee hours of Wednesday morning, “Frankly, we did win this election”—when in truth the race was too close to call—Biden counseled caution. Trump’s statement was rated “egregiously false” by fact-checkers. Biden’s statement hit such a proper note that it got compliments even from Republicans for his “patient” but “confident” message.

With each passing hour, however, it’s looking increasingly likely that the Democrat soon will have to cast aside caution.

While anything is possible in so turbulent a political year as 2020, the headlines and TV tickers now read “Biden on Brink of Win” and “Biden…on Brink of White House.” Biden has already won two of the three states that gave Trump an Electoral College advantage and the presidency in 2016—Wisconsin and Michigan—and the long count in the third state, Pennsylvania, is trending in his favor. Where Trump led by over 500,000 votes on Wednesday in Pennsylvania, his advantage had collapsed on Thursday to barely 78,000 votes. The Trump lead has continued to decline as mounds of mail votes are counted in Philadelphia and other Democratic cities. “The Biden people are very confident. The numbers are moving in his direction right now,” says former Pennsylvania senator Rick Santorum, a Republican who has reviewed the data from the Keystone State counties that are still counting. Pennsylvania Democratic Senator Bob Casey Jr. is blunter. Pointing to the trend lines, Casey declared Thursday afternoon that a Biden win in the state had already become “inevitable.”

When, exactly? “I can’t make that guesstimate,” said Casey. But he added, “No question, I think, Joe Biden will win the state.”

If Biden wins Pennsylvania, he wins the presidency.

By Thursday afternoon, Biden was projected as the winner of states with 253 electoral votes, as compared with 213 for Trump. He needs 270 to win. He can get there most quickly and easily via Pennsylvania, with 20 electoral votes. Or he can go via a combination of states that are still counting—Georgia with 16 electoral votes, North Carolina with 15, Arizona with 11, and Nevada with 6. As of Thursday afternoon, Biden was already ahead in Arizona and Nevada and only narrowly behind in the others. In Georgia, for instance, Trump’s advantage had fallen to less than 10,000 votes.

Biden isn’t going to get ahead of himself. I have covered this man for decades, as a senator, a vice president, and a presidential candidate. I have seen him in triumph and in defeat. After 50 years of bidding for office, he knows when and how a winner gets to declare victory. He will follow the old-school political protocols and wait until the Associated Press has declared him the winner of a sufficient number of states to claim the 270 electoral votes required to take the job from Trump. That’s appropriate and, frankly, appealing in contrast to the petulant president he seeks to replace.

But if and when the moment of victory comes, the former vice president will need to move quickly and decisively. He can’t afford to leave any opening for Trump to claim that a settled result is somehow uncertain.

Fortunately, Biden and his team appear to recognize this. They’ve been proactive in making statements and gently spinning the narrative in their direction. But when the 270 figure is achieved, the former vice president must make it clear that the transition process has begun. This is about more than launching a transition website, as the Biden campaign has already done. This is about putting an exclamation mark on the decision of the people of the United States to end the presidency of Donald J. Trump.

Even if Trump seeks recounts and mounts legal challenges in states that have declared for the Democrat, even if Trump cries “voter fraud” and refuses to concede, Biden has to be firm enough to control the narrative.

Trump is shameless. On Wednesday, he tweeted, “We have claimed, for Electoral Vote purposes, the Commonwealth of Pennsylvania (which won’t allow legal observers) the State of Georgia, and the State of North Carolina, each one of which has a BIG Trump lead. Additionally, we hereby claim the State of Michigan if, in fact, there was a large number of secretly dumped ballots as has been widely reported!”

Twitter tagged that announcement with this message: “Some or all of the content shared in this Tweet is disputed and might be misleading about an election or other civic process.” That was a generous assessment of a delusional set of claims. On Thursday, the president was beside himself, tweeting, “STOP THE FRAUD!” And “All of the recent Biden claimed States will be legally challenged by us for Voter Fraud and State Election Fraud. Plenty of proof—just check out the Media. WE WILL WIN! America First!”

“The President is using Twitter to spread disinformation and undermine the integrity of our election,” says Kristen Clarke, the president of the Lawyers’ Committee for Civil Rights Under Law, which with Common Cause has called for Twitter to suspend Trump “to ensure that its platform is not used to attack the foundations of our democracy.”

When the tide turns against him, this president tweets even more outrageously. If past is prologue, Trump and allies like Rudy Giuliani will not hesitate to lie about election results. They will also create confusion by suggesting that the normal processes of recording results—the reviews of provisional ballots, the counting of late-arriving overseas and military ballots, the formal canvassing of the totals, the legal challenges, the recounts where necessary—bar Biden from declaring victory.

The accepted practice is that when the 270 threshold is passed, the winner stakes the claim. Biden should do that immediately, day or night, spelling out how that win was achieve, explaining the contour and character of the count. He did some of that on Wednesday and Thursday in brief statements on the vote counting. He said Wednesday:

Of special significance to me is that we’ve won with the majority of the American people. And every indication is that that majority will grow. We have a popular vote lead of nearly 3 million votes and every indication is that will grow as well.

Indeed, Senator Harris and I are on track to win more votes than any ticket in the history of this country that ever won the presidency and vice presidency. Over 70 million votes. I’m very proud of our campaign. Only three presidential campaigns in the past have defeated an incumbent president. When it’s finished, God willing, we’ll be the fourth. This is a major achievement. This is a major achievement. And it’s been a long and difficult campaign, but it’s been a more difficult time for our country.

Biden can get to the talk of “healing” and “unity” that are another part of the protocols for any presidents-elect. But he will make things less difficult, for himself and for his country, if he fully embraces the will of the people and declares in clear and unequivocal terms that Trump has been defeated.