THAT OPPOSITION leader Viktor Yushchenko would finish first in the opening round of Ukraine's presidential election was widely expected: The pro-democracy, pro-Western candidate has led in opinion polls for more than a year. What surprised -- and electrified -- many of those who supported him was the acknowledgment of his victory by Ukrainian election officials on Wednesday, 10 days after voters went to the polls. For months Ukraine's corrupt and quasi-autocratic government did its thuggish best to promote the election of the current prime minister, Viktor Yanukovych, by manipulating state-controlled media and assaulting opposition supporters and leaders. Most voters expected the election results to be falsified. That Mr. Yushchenko's lead was belatedly announced is testimony to the pressure from millions of Ukrainians who turned out to vote for him, as well as from Western governments that dispatched thousands of observers and repeatedly warned against fraud.

Mr. Yushchenko must still prevail in a runoff election a week from today -- a race where state media and other government intervention once again make him an underdog despite a wide lead in independent polls. Nevertheless, Ukrainians who hope to steer their country toward liberal democracy have a chance to triumph in a political contest that may be as important to the future of Europe as it is to their nation of 50 million people.

Ukraine's choice is about its future political system and geopolitical alignment. Mr. Yushchenko promises to allow genuine democratic institutions, such as a free press and fair elections, and to seek membership for Ukraine in NATO and the European Union. His opponent would consolidate the corrupt authoritarianism of the current regime and wed it to that of Russian President Vladimir Putin, who aspires to restore Kremlin dominion over Ukraine and other former Soviet republics.

The first round of the elections should have sent a message to Mr. Putin, who blatantly intervened in the campaign by channeling hundreds of millions of dollars to the official candidate and personally campaigning for him in the capital, Kiev, just days before the election. Kiev voted heavily for the opposition, but on Friday Mr. Putin returned again to Ukraine, where he apparently hopes to control the electoral outcome as he has elections inside Russia.

The Bush administration, which has recognized that the United States has "an overriding interest in a democratic Ukraine," has been fecklessly silent about Mr. Putin's intervention. It has, however, pressured Ukrainian officials and allied businessmen to allow a fair vote, in part by threatening to deny them U.S. visas. Sen. Richard G. Lugar (R-Ind.), chairman of the Senate Foreign Relations committee and sponsor of U.S. aid programs for Ukraine, will travel to Kiev with the support of President Bush to observe the second round. Mr. Lugar and Mr. Bush will not and should not campaign for Mr. Yushchenko or any other candidate, as Mr. Putin has done. Their goal need be only that of the vast majority of Ukrainians: a free choice.