Former Starbucks CEO Howard Schultz, who considered 2020 presidential bid, endorses Joe Biden

Former Starbucks CEO Howard Schultz endorsed Democratic presidential nominee Joe Biden on Monday in a message to his email list that warned that "what is at risk is democracy itself."

The coffee titan had publicly mulled the possibility of running in the 2020 race as a "centrist independent" but dropped the plan last September. The prospect of a Schultz bid outside the two-party system spooked Democrats who worried that he could take away votes from the Democratic nominee and potentially throw the race to President Donald Trump.

"While my exploration revealed that a run for office was not the best way for me to give back to a country that has given me so much, I continue to believe that our nation can live up to our ideals, and that we all must envision and fight for a new American future," Schultz wrote in the email.

Schultz wrote that he and his wife, Sheri Schultz, will vote for Biden and donate to his campaign.

Schultz, who has an estimated net worth of more than $4 billion, also wrote that he and his wife will support nonpartisan democracy initiatives aimed at ensuring the legitimacy of the vote and organizations geared toward mobilizing infrequent voters and minorities.

Schultz is among the last of Biden's rivals or would-be rivals to line up behind him. The bulk of the Democratic primary field endorsed Biden months ago, including progressive Sen. Bernie Sanders, I-Vt., who placed second.

Schultz did not gain any traction as a potential candidate in his own right, so whether his political backing will make any difference in the race is uncertain. But his support does lend further credence to Biden's efforts to show support across ideological lines, given Schultz's moderate positioning.

"Trump's defeat is but the first step to repair and rebuild our country," Schultz wrote. "The months and years to follow are a time not for Democrats to exact revenge and enact a far-left agenda."

The announcement comes as another one of the 2020 race's several billionaires, former New York Mayor Michael Bloomberg, steps up his support for Biden. Bloomberg announced Sunday that he would spend at least $100 million to help Biden win in Florida, a key battleground.

Schultz joined Starbucks in the 1980s and served two stints as the company's CEO, from 1986 to 2000 and again after the financial crisis, from 2008 to 2017.