Gov. Scott Walker, in an announcement as abrupt as his fall from presidential frontrunner to also-ran, said Monday that he is suspending his 2016 White House campaign just 70 days after it started.

Few outside Walker’s inner circle saw it coming so soon. Weeks ago, Walker was widely seen as a top contender for the Republican presidential nomination.

But on Monday, national news outlets reported Walker’s campaign, which weeks ago vied for checks from top GOP donors, was out of cash. A day earlier, a CNN/ORC poll had shown Walker’s national support at a new low: less than 1 percent.

In announcing his departure at a hastily scheduled appearance at a Madison hotel, Walker took aim at the fellow Republican candidate whose rise coincided with his decline: businessman Donald Trump.

Walker said his exit from the race would help fellow Republicans coalesce behind a “positive, conservative alternative to the current frontrunner.” He encouraged other GOP candidates to follow his lead.

“Today, I believe that I am being called to lead by helping to clear the field in this race so that a positive, conservative message can rise to the top of the field,” Walker said.

Walker also lamented a Republican presidential race that he said has turned negative. He contrasted that with what he described as the sunniness of his political hero, Ronald Reagan.

“Sadly, the debate taking place in the Republican Party today is not focused on that optimistic view of America,” Walker said. “Instead, it has drifted into personal attacks.”

Walker left the small conference room in The Edgewater hotel immediately after his remarks, declining to take questions from reporters.

It capped an improbable collapse for a candidate who recently registered in polls as the GOP leader in the first-in-the-nation Iowa caucuses and one of the party’s top three candidates nationally.

“This is one of the most precipitous falls in presidential campaign history,” said Charles Franklin, director of the Marquette University Law School Poll.

While Walker’s campaign had struggled in recent weeks as his poll numbers plummeted, few expected him to end his campaign now. He became just the second GOP candidate to exit the race, after former Texas Gov. Rick Perry.

Walker returns to Wisconsin with the bulk of his second term as governor still remaining.

Even his fellow conservatives acknowledge Walker’s political stock in his home state has been weakened after his failed presidential run, frequent absences from the state this year while campaigning and his signing of a controversial state budget in July.

Reprising union fight

Trump’s confrontational brand of conservative populism rose atop the GOP polls buoyed by grassroots frustration with long-time politicians — and owing no small debt to Trump’s flair for showmanship.

All that boded poorly for Walker, a self-described “aggressively normal” candidate and public officeholder of more than two decades.

In an interview with The Washington Post Monday, Trump praised Walker and acknowledged surprise at how his campaign ended.

“I really liked him a lot,” Trump said. “I thought he was a terrific person. He has been a terrific governor. I got to know him pretty well. I’m a little surprised that it hasn’t worked out better for him. Many people thought he’d be the primary competition, at least initially.”

Trump also speculated that Walker may have been distracted by “too many people” surrounding him.

“He was very loose guy when he came up to see me a few months ago to give me a plaque, but then on the campaign, maybe there were too many people. I think he had too many people, many of them who didn’t know what they were doing,” Trump said of Walker, according to the Post.

Walker’s announcement came days after he failed to gain traction in the second GOP debate, and after he said he would scale back his campaign to focus on Iowa.

Heading into the second debate, Walker — whose national profile and presidential aspirations were shaped by his high-profile battle with public worker unions in 2011 — pledged to reprise that fight against federal government worker unions.

But Walker’s labor plan failed to make a splash with Republican primary-goers. Union leaders in Wisconsin and nationally said the country had rejected his anti-labor policies.

“Scott Walker is still a disgrace,” said AFL-CIO president Richard Trumka, “just no longer national.”

Walker came under increasing fire from his own supporters and donors after a second straight lackluster debate performance last week. One of his top donors, Minnesota media mogul Stanley Hubbard, acknowledged after the debate that he was thinking of giving to other candidates who shined in the debates.

Super PAC scramble

At about 3 p.m. Monday, Walker’s campaign revealed he would make an announcement at 5 p.m. at The Edgewater hotel in Madison. Minutes later, reports began to trickle out that Walker would end his campaign.

Some reports highlighted the increasingly cash-strapped plight of Walker’s campaign. The New York Times reported two donors were organizing a fundraiser for Walker in New York City on Thursday “but were struggling to lock in people to attend.”

Keith Gilkes, a close Walker adviser and executive director of Unintimidated PAC, the SuperPAC created to support Walker’s campaign, said in a statement: “Governor Walker has been a warrior for the conservative movement — delivering unprecedented victories that culminated in a bucket list of conservative reforms that changed people’s lives for the better.

“Governor Walker’s decision to gracefully exit the race was no doubt tremendously difficult for him and his family, but it is a testament to the type of man and leader that he is.”

Unintimidated PAC raised more than $20 million through June 30.

The super PAC had only just begun a blitz of advertising expected to bolster Walker in early presidential states such as Iowa and South Carolina. It told federal regulators Friday it had spent more than $1.6 million on behalf of Walker this year. It will return what it hasn’t spent to its donors.

Walker’s announcement set off a scramble among the remaining candidates to obtain financial support from Walker’s top donors.

Topping the polls

Just two months ago, few would’ve predicted Walker’s White House bid would end like this.

Before officially announcing his presidential candidacy in July, Walker spent much of 2015 near the top of polls of Republican candidates nationally and in early presidential states such as Iowa.

A widely publicized series of confrontations with unions in Wisconsin during his five years as governor launched him onto the national stage. And a breakout performance at the Iowa Freedom Summit in January propelled him into the first rank of GOP contenders.

He remained there much of the spring and summer — despite occasionally raising eyebrows, including once comparing union protesters to Islamic terrorists.

But then came Trump, and August and September proved disastrous for Walker. His performances in the first two presidential debates were widely panned. They were accompanied by a series of unforced gaffes on issues such as immigration, and an interview in which he appeared to express openness to building a wall on the U.S.-Canadian border.

Walker’s exit from the race marked a rare defeat in a political career otherwise filled with victories.

The only comparable moment in Walker’s career came in 2006, when he exited the race for Wisconsin governor to allow Mark Green to claim the Republican nomination — and earn some good will within the party.

In Wisconsin, Democrats who’ve so often been beaten by Walker cheered his departure from the presidential fray.

Outside the hotel where he announced his exit, a small throng of protesters gathered to sing joyfully. One of them, Joanne Swarzberg of Madison, said her only regret is she wouldn’t get to continue to watch Walker flounder on the national stage.

“That’s the only shame in him dropping out: It’s been fun watching him go down,” Swartzberg said.

Others, such as state Senate Democratic Leader Jennifer Shilling, called Walker’s exit a repudiation of his message.

“The lack of support for Governor Walker’s presidential campaign is a clear rejection of ‘divide and conquer’ politics,” Shilling said in a statement.

Meanwhile, Assembly Speaker Robin Vos, R-Rochester, said in a statement that “Wisconsin is fortunate to have Governor Walker for four full years.”

Walker has an “amazing story to tell about turning Wisconsin around,” Vos said. “It is unfortunate that the bluster of candidates overshadowed his substance.”