“We don’t want migrants to come to Hungary,” he said. “They are unwilling to integrate and they respect only their own laws. They want a war; they are brought to Europe by ISIS.”

Others expressed concern over the long-term consequences of Sunday’s vote.

Istvan Hegedus, the chairman of the Hungarian Europe Society, a research institute, was an early member of Fidesz, at a time when Mr. Orban was a firebrand champion of democracy after three decades of Communist rule.

But Mr. Hegedus left the party in 1994 and says he has watched with alarm as Mr. Orban has transformed himself from a centrist friend of the West into the leader of a crusade to create what Mr. Orban himself calls an “illiberal democracy.”

“At each step on this path, the European politicians have proven ineffective,” Mr. Hegedus said. “I think the mistake they made was they viewed him as an enfant terrible, but someone they could deal with. They convinced themselves that we know this man and that there is really nothing at stake.”

Sunday’s election, he said, was the best — and perhaps, last — chance for Hungary to change course.

Jozsef Peter Martin, the executive director of Transparency International Hungary, an anticorruption advocacy group, said the election was conducted on an unfair playing field. He compared the vote to playing soccer on a field set at a 45-degree angle.

“The whole institutional system is swayed to one party,” Mr. Martin said. From the state-controlled news media to the gerrymandering of electoral districts to favor Fidesz, an already fragmented opposition found it hard to compete, he said.

Under the current system, put in place in 2012, voters cast two ballots. One is for a national list, with parties awarded seats in Parliament based on the percentage of votes. That accounts for 93 of the 199 seats.