The Mercer family used part of its billions to create Donald Trump. During the GOP primaries it supported Ted Cruz. It switched its support to Trump after Cruz lost important state primaries. The Mercer family invested in a British data firm that became known as Cambridge Analytica in order to build a populist political organization. Steve Bannon, who became Trump's campaign manager during the general election, was in charge of using Cambridge Analytica to test populist messages that would appeal to young white conservatives in the US. They identified the ideas of "the deep state" and the "drain the swamp" message which became central to the Trump campaign. They also found that anti-immigration messages, anti globalism messages, and certain types of racist messages, appealed to white Americans with a populist leaning. Donald Trump rode those messages to the White House.
The messages that Trump used to win the election were primarily campaign messages for his base. He liked them as long as they worked with his base, but he ended up filling the swamp with establishment Republicans who are more interested in cutting taxes for the rich, deregulation, and cutting spending on social welfare programs. Steve Bannon became an outsider in the White House and he was eventually removed from his powerful position. He returned to his position as the head of Breitbart News. He eventually made the mistake of criticizing Donald Trump and the Mercer family, which owns Breitbart News, replaced him with a Trump loyalist. Bannon is now promoting his populist ideology in Europe.