Democratic presidential candidate Sen. Bernie Sanders, I-Vt., right, with his wife Jane, speaks during a campaign event in San Antonio, Saturday, Feb. 22, 2020. (AP Photo/Eric Gay)

SAN ANTONIO (AP) — By the fall of 2018, when Democrats were promoting a slate of centrist candidates to topple Republicans in Congress, Bernie Sanders was seeing a very different picture.

The Vermont senator and avowed democratic socialist was convinced his most fervent supporters were as energized as ever, ready to rally around the political insurgency flag he planted in 2016. He could keep stoking the deep frustration and mistrust of the political system and attract backers who had felt too disillusioned to bother voting in the past — much like President Donald Trump had on the right.

Sanders, 78, the oldest candidate in the race, also saw his unwavering commitment to universal health care, combating climate change, canceling student debt, and tuition-free college continuing to excite young people, including Latinos who came to call him “Tio” (uncle) Bernie.

And, most importantly, he was sure he’d have the money, enough consistent financial backing built on mostly small donations made online from around the country, to finish what he started in 2016, rising from an unknown nationally to a credible challenger to Hillary Clinton for the Democratic presidential nomination.

This time, Sanders’ movement has a political machine to propel it.

“Last time, we really did not know how this would go with our fundraising model,” said Jeff Weaver, Sanders’ senior adviser. “It ended up being $240 million, but we had no way of knowing that in the spring of 2015, so we were very slow to staff-up in early states. This time, we did things very differently.

“We knew we were a front-runner.”

Now everyone else knows it, too. Sanders’ lopsided win Saturday in Nevada caps his remarkable transformation from political insurgent to possibly even a favorite to face off with Trump in November. Both have campaigns built on mobilizing die-hard loyalists but also disaffected voters — even though their politics are polar opposite.

“The Trump Democrats are people that got abandoned by the Democrat Party and Bernie was straightforward about that,” said Jim Hightower, a populist former Texas agriculture commissioner who endorsed Sanders in 2016 and remains loyal to him.

Sanders’ impressive campaign bank account has helped keep many others loyal to him as well. He raised nearly $96 million by the end of last year, raked in an additional $25 million in January and has vowed to raise and spend $1 billion to defeat Trump in November. His donors are like a faucet that he can turn on as needed because they contribute in small amounts, with little concern of exceeding federal limits.

That stream of cash has also meant Sanders could build a more professional operation, with longer-range planning and better organizational structure.

His last campaign didn’t even have a human resources department, something that allowed multiple accusations of sexual harassment among staff to fester and forced Sanders to apologize before launching his 2020 bid. This time, Sanders has emphasized hiring more women and minorities to top positions, including Faiz Shakir, a Pakistani-American, who is the first Muslim to manage a major presidential campaign.

It’s a money advantage that few of his competitors can match.

Beyond money and organization, Sanders has also worked to better frame issues. After he struggled in 2016 with foreign policy, Sanders spent the years between presidential runs giving speeches about America’s place in the world and became an especially vocal critic of U.S. efforts to help Saudi Arabia fight a war against insurgents backed by Iran in Yemen.

He also worked for change within the structure of the national Democratic Party, muscling through rules changes that helped his campaign this time. “Superdelegates,” mainly elected officials and party leaders, helped Clinton secure the party’s nomination four year ago. Sanders supporters helped force a change to limit their influence during the national convention coming up this summer in Milwaukee.

And his campaign drove changes in the way that Iowa reported its caucus results by reporting voters’ first preference in addition to how many delegates a campaign won. That’s allowed Sanders to crow about edging Pete Buttigieg, the former mayor of South Bend, Indiana, in the popular vote, even though the pair essentially tied in the number of delegates awarded.