U.S. President Donald Trump on Friday threw his support behind Hungarian populist nationalist Prime Minister Viktor Orbán, who is facing the most serious challenge to his rule in more than a decade in the parliamentary election set for April.

“Viktor Orbán is a true friend, fighter, and WINNER, and has my Complete and Total Endorsement for Re-Election as Prime Minister of Hungary — HE WILL NEVER LET THE GREAT PEOPLE OF HUNGARY DOWN!” Trump wrote in a post on Truth Social.

Relations between Budapest and Washington have reached “new heights of cooperation and spectacular achievement” under the two leaders, Trump wrote.

Trump’s backing of Orbán is in line with the U.S. National Security Strategy unveiled in December, in which the Trump administration vowed to bolster “patriotic European parties.”

Orbán has long been a close ally of Trump and was among the first European leaders to endorse his 2016 presidential bid. Orbán’s nationalist Fidesz party has become a model for MAGA populists, especially for its hard-line approach to minority rights and migration.

Trump also aligned himself with Orbán over Hungary’s decision to continue buying Russian oil, even as Europe sought to reduce dependence on Moscow’s energy supplies. The White House later gave Hungary a one-year exemption from U.S. sanctions on buying Russian oil.

Hungary’s April 12 parliamentary election could threaten Orbán’s long grip on power, amid long-standing criticism over the erosion of democracy and rule-of-law issues. He faces a challenge from his former ally-turned-archnemesis, Péter Magyar, who leads the opposition Tisza party, currently running 12 points ahead in opinion polls.

The election in Hungary, with a population of 9.6 million, represents the most consequential in Europe this year. Orbán has become a key disrupter in the EU, frequently clashing with Brussels and other European capitals on support for Ukraine, LGBTQ+ rights and Russia sanctions, many times stalling urgent decisions.