The votes that ended Michael Brennan’s term as mayor of Portland were counted a long time before Tuesday night.

He wasn’t done in by the famous 5-4 votes on the City Council that challenger Ethan Strimling cited as proof that the city was divided and needed new leadership.

But Brennan’s boat started to leak in June of 2014, when voters rejected his initiative to sell two-thirds of Congress Square Park (or Congress Square Plaza if you thought the sale was a good idea) to the next-door Westin Hotel.

No one issue should make or break a candidate, and Brennan had a strong record for someone seeking a second term. Just this year, he pushed through a city minimum wage increase and aid to asylum-seeking immigrants that had been cut off by the LePage administration. Both should have been dramatic achievements in Maine’s most liberal city.

But when the Congress Square issue went to referendum, Brennan was the face of the Vote No campaign, and when the referendum lost (by only 283 votes) he was the face of that too.

And that loss has haunted him.

A former colleague of Brennan’s from the Maine Legislature was astonished recently to see how such a liberal lawmaker could be attacked by left-wing opponents.

He asked: “When did Mike Brennan become ‘The Man?’ ”

It was right after Congress Square.

Sure, it’s unfair.

Brennan wasn’t alone in his position. The City Council voted 6-3 to back the sale and the business community was convinced that the creation of an event space at the Westin would activate a part of town that was not reaching its potential.

And Brennan wasn’t wrong in his assessment – at least I didn’t think so.

Our editorial board supported the sale because we thought it would be a good deal to trade part of an underused park for a revitalized public plaza that crossed Congress Street and went all the way to the door of the Portland Museum of Art.

We also agreed with Brennan that a referendum was the worst way to decide a land-use policy question.

But government is about more than being right. You have to win, too.

Brennan got the votes he needed at the City Council. What he did not do – what he probably could not do – was explain why selling this public asset would better serve the public than keeping it. He could not explain how a development that catered to rich people could indirectly help everyone, or how giving a little here could gain a lot somewhere else.

He didn’t give himself time to make the case, responding to the Westin’s schedule instead of the park’s supporters’.

Believing that he was right, he didn’t listen to the people who said he was wrong, and they got to frame the debate: In their view, the people had to act or we would lose all of our parks to development.

The victorious park referendum planted the seeds for this election. It created an opportunity for someone to run against Brennan, and 2011 second-place finisher Ethan Strimling is nothing if not opportunistic.

Eight weeks before the 2014 election, Baldacci Communications released a poll which showed city residents opposed the sale by a 14-point margin.

The poll had been conducted on “behalf of a client who had concerns about the sale,” said Baldacci Communications President Stephanie Clifford.

This fall, Clifford was Strimling’s campaign manager.

After the 2014 loss, many of the people who had been on Brennan’s side have turned against him. Councilors Nick Mavodones, Jill Duson, Ed Suslovic and former Councilor Cheryl Leeman, who all voted to sell the park, all ended up endorsing Strimling.

So did the Chamber of Commerce, even though Brennan carried their water in the Congress Square campaign.

And, so did the editorial board of this newspaper. We agreed with Brennan on Congress Square (and almost every other issue) but we came to the conclusion that there’s only one real power that a mayor has in Portland’s system, and that is the power to persuade.

Congress Square showed that Brennan could push a vote through the council, but couldn’t organize a campaign to reach the people who will never go to a council meeting.

Strimling with his experience as a TV commentator might be able to do better at that part of the job.

But he should take a lesson from Brennan: Even when you are right, you can still lose.

And once things go bad, there are no second chances.