SEATTLE -- For a businessman who grew a small coffee roaster into an inescapable global chain, who ensured that even his part-time workers had benefits and who has given about $150,000 to Democratic campaigns, former Starbucks Chairman Howard Schultz is generating tepid -- or even hostile -- responses within the party as he weighs a presidential bid in 2020.

That's partly because -- as Schultz told "60 Minutes" on Sunday -- he's considering running as an independent, a prospect many worry could draw support from the eventual Democratic nominee and hand U.S. President Donald Trump another four years in office. Among those urging him not to run as an independent are David Axelrod, the former adviser to President Barack Obama, and Tina Podlodowski, the Democratic Party chairwoman in Washington state, where Schultz has lived for decades.

"For somebody who is professing to be a lifelong Democrat, I think to be running as in independent in this particular cycle is not a wise thing to do," Podlodowski said.

Julian Castro, the former secretary of Housing and Urban Development who announced a bid for the Democratic nomination this month, said Sunday on CNN he is concerned that if Schultz did run an independent campaign "it would provide Donald Trump with his best hope of getting re-elected."

The 65-year-old Seattle billionaire launches a tour Monday to promote his latest book, "From the Ground Up: A Journey to Reimagine the Promise of America." He has stops this week in New York; Tempe, Arizona; Seattle; and San Francisco -- but no dates listed for the early voting states of Iowa or New Hampshire.

He's been mentioned as a potential candidate many times before, and he's done little to quell speculation about his presidential ambitions since saying when he retired from Starbucks last June that his future could include "public service."

His office did not respond to an email seeking comment about his intentions. If he were to enter the race he would be the most high-profile candidate without prior elected experience.

On paper, Schultz offers a number of qualities that might appeal to voters. He grew up in public housing in Brooklyn, New York, and became the first person in his family to graduate from college.

He took over Starbucks when it sold only coffee beans, not cups -- it had 11 stores and fewer than 100 employees at the time -- and grew it into a global behemoth that now has close to 30,000 stores in 78 countries. Along the way he adopted an ethos of corporate responsibility, making Starbucks one of the earliest U.S. companies to offer stock options and health insurance even to part-time employees, and more recently partnering with Arizona State University to cover tuition for workers who want to earn their bachelor's degree online.

He's waded into contentious social issues. In 2013, Starbucks asked customers not to bring guns into stores following the Sandy Hook Elementary School shooting, and in 2015, Schultz drew anger and ridicule after he urged baristas to write "Race Together" on cups to spark conversations amid tension over police shootings of black men. Last year, after two black men were arrested in a Philadelphia Starbucks while waiting for a business meeting, Starbucks closed 8,000 U.S. stores early so employees could take anti-bias training.

He's been a longtime Democratic donor, contributing to the campaigns of former President Barack Obama, Hillary Clinton, New York Sen. Chuck Schumer, and Washington Sens. Patty Murray and Maria Cantwell, among others. He has also criticized Trump, telling employees that the president was creating "chaos" and hurting business; calling Trump's tax cuts for corporations unnecessary and reckless; and vowing to hire 10,000 refugees after Trump issued an executive order banning travel from seven mostly Muslim nations.

But some of his views might clash with a Democratic Party gearing up to unseat Trump. While some potential nominees, including Massachusetts Sen. Elizabeth Warren and California Sen. Kamala Harris, have endorsed single-payer health care, heavily taxing the rich or free tuition at public colleges, Schultz has criticized some such proposals as unrealistic and instead emphasized expanding the economy and curbing entitlements to get the national debt under control.

"It concerns me that so many voices within the Democratic Party are going so far to the left," Schultz told CNBC last June. "I ask myself, 'How are we going to pay for all these things?' in terms of things like single-payer or people espousing the fact that the government is going to give everyone a job. I don't think that's realistic."

Will Stiles worked at Starbucks for 17 years. The company's culture was laid-back when Schultz arrived, with workers wearing cutoffs and flip-flops, and stores sometimes closing for days at a time so employees could go to a resort, he said. Schultz wore suits.

"He's all, 'Clean this! Clean that!' and he's got shiny shoes," Stiles said. "We were like, who is this guy?"

But Schultz had vision and drive, and he had the workers undergo training in sales and in the product, Stiles said. By offering stock options and benefits, he involved the employees in Starbucks' success. Stiles said he believes Schultz could similarly inspire Americans to be more invested in the country's future.

Still, Stiles, a staunch Democrat, hopes Schultz doesn't run as an independent for fear it could help Trump.

"It would be a shame if he somehow assisted this guy to become a two-termer," Stiles said.