Why does this election matter?

The Slovak presidency is a largely ceremonial post, but the election has been closely watched as a test of strength between political forces that want the polarized Central European country to follow Hungary in embracing President Vladimir V. Putin of Russia and those that want to keep the country aligned with the West.

In a first round of voting on March 23, two candidates on opposing sides — Ivan Korcok, a veteran diplomat hostile to the Kremlin, and Peter Pellegrini, a Russia-friendly politician allied with Slovakia’s populist prime minister — finished ahead of seven other candidates. But neither won the majority needed to avoid a runoff.

The two men will face each other in a second round on Saturday. Opinion polls show them running neck and neck.

The race started with 11 candidates, several of them belligerent nationalists who favor close relations with Russia. Two dropped out before the vote in March.

The departing president, Zuzana Caputova, a stalwart supporter of Ukraine, used her limited powers and the bully pulpit to try to block Prime Minister Robert Fico of Slovakia from taking the country on the same path as Hungary. Prime Minister Viktor Orban of Hungary has tilted away from NATO and toward Moscow, gained a tight grip on the news media and limited the independence of the judiciary.

In the first round, Mr. Korcok, a former ambassador to the United States and an ally of Ms. Caputova, received 42.5 percent of the vote, compared with 37 percent for Mr. Pellegrini.

Mr. Korcok’s strong result exceeded what pre-election opinion polls had predicted and delivered a blow to Mr. Fico. The prime minister was hoping for a resounding win by Mr. Pellegrini, who shares his skepticism of supporting Ukraine.

Mr. Fico returned to power after a general election in September, reviving a political career that many considered over when he resigned in disgrace as prime minister in 2018. He quit amid large street protests and a swirl of corruption accusations after the killing of an investigative journalist who had been looking into government graft.

Mr. Fico wants to reverse Slovakia’s previously robust support for Ukraine. He has also sought to overhaul the judicial system to limit its ability to prosecute corruption. Ms. Caputova opposed both these goals and delayed legislation relating to the judiciary by sending it for constitutional review.

A victory for Mr. Pellegrini in the runoff vote on Saturday would most likely free the government to weaken the judiciary and to take a more combative stance in the European Union over policy toward Ukraine.

Constrained by a president who opposes his policies, Mr. Fico, unlike Mr. Orban, has so far avoided trying to block E.U. assistance to Ukraine and siding openly with Hungary against far bigger and more powerful European countries. Slovakia’s population is less than 5.5 million.

Who is expected to win?

Mr. Pellegrini could benefit on Saturday from voters who in the first round supported the third-place finisher, the anti-NATO nationalist Stefan Harabin, who won about 12 percent of the vote after campaigning on promises to defend traditional Slovak values against homosexuals and immigrants and to promote closer ties with Russia. But Mr. Harabin has denounced both Mr. Korcok and Mr. Pellegrini as liberals, so many of his voters may not vote in the second round.

Victory for Mr. Pellegrini on Saturday would remove a brake on Mr. Fico’s ambitions. A win for Mr. Korcok would most likely lead to a replay of the current standoff between the government and the president.

When will we learn the result?

The timing of results of the second round will depend on how close the race is, but the winner should be clear late Saturday.