WASHINGTON — Presidents have long been known to use ambassadorships as a reward for political and financial support, and President Donald Trump has been no exception.

As of Thursday, Trump has nominated 25 ambassadors out of the 77 posts he now gets to fill.

Eighteen of the picks are political appointments, meaning they were nominated based on their personal ties to Trump. These are the more desirable postings, like those in Europe.

The nonpolitical career appointments usually go to long-serving State Department diplomats with experience in less-coveted regions, such as Africa.

Of the 18, six are known to have made significant financial contributions to the Trump Victory Fund, while the other 12 nominees do not appear to have made any identifiable personal donations to the campaign.

Only nine of the 44 political appointees that former President Barack Obama made did not donate to his campaign.

But because Trump declines to release information about his campaign’s bundlers — who work to gather contributions from friends and family — it is possible the 12 nominees offered help to Trump’s fundraising effort.

Most previous presidential candidates have released information about their bundlers.

It’s possible that supporters made personal donations to groups not required to disclose contributors.

Of those known to have donated to Trump’s campaign, six donated an average of $237,000 to the Trump Victory Fund, according to data from the Federal Election Commission. Most also donated to the Republican National Committee, with an average donation of $71,000.

In the Obama administration, private donations averaged $190,000 and bundler donations averaged $469,000, although details on some of these donations are only in a range of possible contributions.

When factoring in bundler data, political ambassadors under Obama donated an average of $398,000 in private or bundler donations, according to a 2012 study looking at historical trends in ambassadorships.

During his campaign, Trump said he would “drain the swamp” of political insiders, something critics are now questioning. White House spokeswoman Sarah Huckabee Sanders defended Trump’s ambassador nominations, saying in June that “it’s pretty traditional that you would have somebody supportive of you and your agenda to go out and be an ambassador to speak on behalf of the administration.”

Although the Foreign Service Act does not allow presidents to consider political donations when nominating an ambassador, both parties benefit from the practice, so it hasn’t received much pushback from legislators, according to Dennis Jett, former ambassador and co-author of the 2012 study.

As of mid-July, six of Trump’s ambassador nominations have been confirmed by the Senate. Two of those appointments are career positions. This is fewer confirmations than usual at this point in a presidency, which Trump blames on the Democrats, who in turn blame the administration’s slow pace in nominating.

Trump did not allow any political appointees from the Obama administration to apply for an extension of their terms, meaning he has more positions to fill than usual. Of the 188 total ambassadorships, 52 positions are vacant and do not have any nominations.

Here are the six nominees known to have donated to Trump:

Kelly Knight Craft, head of the business advisory firm Kelly G. Knight LLC, who donated about $260,000 to the Trump Victory Fund and about $16,600 to the Republican National Committee, as ambassador to Canada.

Lewis Eisenberg, co-founder of Ironhill Investments, which donated $35,800 to the Trump Victory Fund and $25,000 to the Republican National Committee, as ambassador to Italy and San Marino.

George Edward Glass, owner of MGG Development and former president of Pacific Crest Securities, who donated more than $77,000 to the Trump Victory Fund and $38,400 to the Republican National Committee, as ambassador to Portugal.

Doug Manchester, chairman of Manchester Financial Group, who donated more than $500,000 to the Trump Victory Fund and about $222,000 to the Republican National Committee, as ambassador to Bahamas.

Jamie McCourt, former co-owner of the Dodgers, who donated about $400,000 to the Trump Victory Fund, as ambassador to Belgium.

Robert Wood Johnson IV, chairman and chief executive of the Johnson Co. and owner of the NFL’s New York Jets; who donated $100,000 to the Trump Victory Fund, $5,000 to Trump for President and $151,000 to the Republican National Committee; as ambassador to Britain.

Here are the 12 whose financial support could not be verified:

Terry Branstad, former Iowa governor, as ambassador to China. His nomination has been confirmed by the Senate.

Scott Brown, former lawyer and U.S. senator, as ambassador to New Zealand. His nomination was confirmed by the Senate in June.

Kelly Eckels Currie, formerly with the State Department, as ambassador to the United Nations Economic and Social Council.

Sharon Day, who has served as co-chair for the Republican National Convention three consecutive election cycles and donated $10,000 to the RNC, as ambassador to Costa Rica.

David Friedman, Trump’s longtime bankruptcy lawyer, as ambassador to Israel. His nomination was confirmed by the Senate in March.

Callista Gingrich, president of Gingrich Productions and wife of former House Speaker Newt Gingrich, as ambassador to the Vatican.

William Francis Hagerty IV, former member of the Tennessee governor’s Cabinet and a member of the 2016 Trump presidential transition team, who donated $33,400 to the Republican National Committee, as ambassador to Japan. His appointment was confirmed last week.

Nikki Haley, ex-South Carolina governor, as ambassador to the United Nations. Her nomination was confirmed by the Senate in January.

Kay Bailey Hutchison, former U.S. senator from Texas, as ambassador to NATO.

Stephen King, a businessman and Republican Party activist, as ambassador to the Czech Republic.

K.T. McFarland, formerly on the National Security Council, as ambassador to Singapore.

Jay Patrick Murray, formerly with the State Department’s Bureau of Political Military Affairs, as ambassador for Special Political Affairs at the U.N.

lauren.rosenblatt@latimes.com