By Jason Stein, Patrick Marley and Mary Spicuzza

With his prospects and funds dwindling, Wisconsin Gov. Scott Walker dropped out of the race for president Monday, saying he wanted to clear the way for a conservative optimist to take down real estate mogul Donald Trump.

At a hastily organized news conference at the Edgewater Hotel, Walker also encouraged others in the packed GOP field to pull out.

"Today, I believe that I am being called to lead by helping to clear the field in this race for a positive conservative message to rise to the top of the field. With this in mind, I will suspend my campaign. I encourage other Republican presidential candidates to consider doing the same so that the voters can focus on a limited number of candidates who can offer a positive conservative alternative to the current front-runner," Walker said.

Walker had faced a series of daunting setbacks over the past six weeks but the news surprised supporters and donors. His withdrawal adds another twist to a GOP primary campaign already unsettled by the current strength of Trump and other outsider candidates.

Walker, the son of a Baptist minister who ran successfully for the state Assembly, Milwaukee County executive and three times for governor, has previously spoken about being called to run for office. But on Monday, he cited his faith in his decision to leave the race.

"When I was sitting in church yesterday, the pastor's words reminded me that the Bible is full of stories about people who were called to be leaders in unusual ways," Walker said. "Today, I believe that I am being called to lead by helping to clear the field so that a positive conservative message can rise to the top of the field."

The governor spoke for just 4 minutes in a room with only a rostrum and state and national flags. He recognized the death Monday of Wisconsin Supreme Court Justice N. Patrick Crooks but declined to take reporters' questions, leaving the room as quickly as he had come.

Walker has more than three years left in his second term. Already, the governor has engineered a conservative shift in a battleground state, rolling back union bargaining power, cutting taxes and enacting limits on abortions and access to concealed-carry permits for gun owners.

His campaign didn't immediately address the next steps for him as a governor or as a Republican whose endorsement will be sought by other White House contenders. Walker has long favored other governors and conservatives as potential presidents and his reference to positive alternatives to Trump could cover several other candidates such as former Florida Gov. Jeb Bush and U.S. Sen. Marco Rubio of Florida.

Praise rolled in from some of those GOP candidates.

"Scott Walker is a good man who entered the presidential race after winning three grueling campaigns in four years," Rubio said in a statement. "He remains one of the best governors in the country."

"Scott Walker is a good man who has a proven record of fighting for conservative reforms. I know he'll continue to do that as Governor," Bush posted on Twitter.

Walker opponents, such as American Federation of Teachers President Randi Weingarten, had a different take.

"As Governor Scott Walker leaves this race, this is much clear: You can't build a campaign by tearing working people down and attacking their aspirations for a better life," Weingarten said.

After Wednesday's debate _ the second for the GOP presidential candidates _ Walker was upbeat about his performance and said that he would be focused on delivering more passion in the race. But one GOP source familiar with the campaign's situation said that with his late official announcement and aggressive spending, Walker was encountering difficulties raising enough money to maintain a staff of about 90 across the country.

"If it wasn't for cash flow, he'd still be here," the source said.

Walker's withdrawal Monday came after a meeting in Madison that morning that was attended by advisers such as campaign chairman Mike Grebe and pollster Ed Goeas. The governor's campaign manager, Rick Wiley, was not present, the source said.

Over the weekend, Walker had indicated he would focus more on Iowa, Wisconsin's neighboring state that holds the country's first presidential caucus, telling Bloomberg News that he planned to spend 10 or more days a month there and that the campaign was on top of its bills.

Walker donors such as broadcasting billionaire Stanley Hubbard of Minneapolis reacted with surprise to the announcement. Hubbard said he hadn't known it was coming and wished Walker had remained in the race.

Instead, Walker joins former Texas Gov. Rick Perry as one of the first presidential candidates to drop out of one of the most robust Republican fields in years. Walker is withdrawing before longshots such as Louisiana Gov. Bobby Jindal, U.S. Sen. Lindsey Graham of South Carolina and former New York Gov. George Pataki.

Walker's message Monday was in part aimed at such candidates.

"I encourage other Republican presidential candidates to consider doing the same, so that the voters can focus on a limited number of candidates who can offer a positive conservative alternative to the current front-runner," Walker said of dropping out.

Walker's White House campaign charted a course this year that looked like a mountain, with a steep, surprising rise last spring to front-runner status in Iowa followed by an equally stunning crash in recent weeks that bewildered many longtime supporters.

When faced with similar challenges during his first unsuccessful bid for governor in the 2006 GOP primary, Walker also chose to drop out rather than fight a questionable campaign against a fellow Republican. That move cemented his status among many Republicans in Wisconsin and helped set up his successful 2010 run.

Speculation in recent days had focused on whether Walker's hobbled 2016 campaign could have ever recovered financially from its recent setbacks. Observers were watching for signs he would cut back on his staff or replace Wiley.

Last spring and early summer, Walker rode high among polls and pundits alike, allowing his allied political group, the super PAC Unintimidated, to raise nearly $20 million between April and June alone. But during that time the governor was not an announced candidate for the White House and couldn't raise money for his actual campaign under federal election rules.

The super PAC recently started running ads promoting Walker in Iowa, but likely still has millions of dollars left in the bank. A spokesman for the organization said it would soon wind down its ad campaign and return any leftover sums to its donors.

Former Walker advisers and staff weighed in on social media Monday afternoon about the governor's decision to drop out.

Dan Blum, a deputy campaign manager for Walker during his 2012 recall election victory, tweeted that it was a mistake for candidates to focus on what GOP voters want or appear to want in 2016. Some of the sharpest critiques of Walker's campaign focused on what some said amounted to shifting his positions on issues such as immigration in an attempt to dial in support from the Republican electorate.

"Walker is a great man, wonderful father and husband, very good R(epublican) governor in a blue state. But he strayed from himself. Always a killer," Blum tweeted.

Blum works for GOP media strategist Liz Mair, who was forced off the Walker campaign in March for tweets criticizing Iowa, the support for ethanol subsidies there and its first-in-the-nation caucuses. That episode was the first in a series of setbacks that dogged Walker's campaign on its way to its conclusion Monday.

"It's not surprising from the perspective of the last few weeks," said Larry Sabato, a national political observer, who gave credit to Walker for getting out early.

Sabato said that Walker was a front-runner who was leading polls in Iowa and elsewhere for months earlier this year.

"Some contenders look good on paper, but when they actually get out on the stump they fail to live up to their own hype," Sabato said. "I think he suffered a bit from a lack of preparedness."

Sabato said he seemed especially unprepared on foreign policy issues.

"He relied to heavily on a memorized speech," Sabato said. "People talked about Scott Walker, the automaton."

Charles Franklin, director of the Marquette University Law School Poll, said the news came as a surprise because he assumed Walker "had enough money to keep going for a while."

"That said, the collapse in the polls since July has been one of the more spectacular collapses in presidential campaign history," Franklin said.

(Jason Stein and Patrick Marley reported for this story from Madison, with Mary Spicuzza in Milwaukee.)

(c)2015 Milwaukee Journal Sentinel