BERLIN — Germany’s highest court ruled in favor of the far-right Alternative for Germany party in its case against the country’s sitting interior minister on Tuesday, a symbolic victory for the populist party that has been steadily losing support in recent months as the country’s response to the coronavirus has dulled the appetite for criticism of the government.
Alternative for Germany, known by its German initials AfD, is the country’s largest opposition party, and took legal action against the interior minister, Horst Seehofer, over a 2018 interview in which he warned that the party endangered the German state.
In its decision, the court focused on the fact that the interview, conducted by the German news agency D.P.A., was also posted on Mr. Seehofer’s ministerial website.
The court defended Mr. Seehofer’s right to make the comments, but it took issue with the use of government resources to promote political speech.
“The admissibility of the federal government’s public relations work ends where advertising for, or influence against, individuals in the political competing parties or persons begins,” Andreas Vosskuhle, the court’s outgoing president, said on Tuesday.
Mr. Seehofer became interior minister in March 2018, under the fourth coalition government of Chancellor Angela Merkel. In the interview, conducted in September of that year, Mr. Seehofer criticized the AfD’s verbal attack on the president of the German Parliament. “They stand against this state,” he told the D.P.A. In another part of the interview, Mr. Seehofer characterized the AfD’s actions as destructive to the state.
The interview was posted on the government’s website for several weeks. The AfD tried to secure an emergency injunction at the time, but the court rejected the request.
Günter Krings, a representative of the interior ministry, pledged on Tuesday to vigilantly check future reports posted on the ministry’s website. He added: “We are very pleased that the court has established with truly gratifying clarity that a federal minister of the interior, even Horst Seehofer, can also take part in the political battle of opinion.”
The decision, handed down Tuesday morning, gives the AfD a rare victory at a time when it has struggled to connect with voters during the coronavirus outbreak. The German government’s response to the pandemic has been widely seen as successful, bolstering its popularity.
The AfD’s image has also been hurt by the decision by the domestic intelligence service to classify a branch of the party as an extremist group, which has led to prolonged infighting between party’s far-right and conservative factions.
A recent poll showed the party at just 8 percent support, its lowest numbers since it garnered nearly 13 percent of the votes cast in the 2017 national election.
“The established parties may play with morality, we have the law on our side!” Tino Chrupalla, a party leader, wrote in a statement after the court ruling.
The judgment is largely symbolic: It did not include any penalties for Mr. Seehofer, and the interview at the heart of the matter has not been on his website for more than a year.
The AfD has a history of attempting to use courts to legitimize its view that it is a victim of establishment politics, despite being the largest opposition party in the country’s 709-seat parliament, the Bundestag.
Last month, a Berlin court rejected the party’s suit to force the domestic intelligence service from mentioning two of the party’s extremist branches — including the party’s youth wing — in its annual report.
But the AfD has won a similar case against a former government official. The official, Johanna Wanka, explicitly criticized an AfD demonstration in a press statement in 2015, when she was the education minister. The court ruled in 2018 that Ms. Wanka was wrong to use her government position for politics.