UKRAINIAN PRESIDENT Viktor Yanukovych has a dilemma. He took office last year promising to lead his country toward economic integration with the European Union, which is what Ukraine’s big industrialists as well as most of its citizens want. But Mr. Yanukovych also wants to concentrate power in his own hands and to punish his political enemies — especially the leaders of the 2004 Orange Revolution, which reversed his previous, fraudulent election as president. He has been slow to realize that he cannot do both.

Mr. Yanukovych made his first foreign trip to Brussels — no doubt irritating Russian Prime Minister Vladimir Putin, who directed the Ukrainian’s failed attempt to steal the presidency in 2004. He has been talking with the E.U. about an association agreement that would give Ukraine preferential trade terms and, Kiev hopes, visa-free travel. Ukraine has substantial support within the E.U.; a group of countries led by Poland has been pressing its cause.

Yet Mr. Yanukovych has also been pushing ahead with the prosecution of top leaders of the Orange Revolution and the government he replaced. Chief among those targeted is Yulia Tymoshenko, a former prime minister. For several weeks Ms. Tymoshenko has been on trial in Kiev on flimsy charges of malfeasance during her time in office. Last Friday, after she taunted the judge and a witness, she was jailed on contempt charges.

Mr. Yanukovych’s spokesmen contend that Ms. Tymoshenko is only one of hundreds of people being investigated on corruption charges, and that most are not opposition figures. The foreign ministry argues that the flamboyant opposition leader’s behavior would have led to her jailing in a U.S. court — which seems most unlikely. In reality, the Obama administration and European governments have been unanimous in saying that Ms. Tymoshenko’s prosecution appears political and her jailing unjust. Even Russia issued a statement, saying the gas deal that Ms. Tymoshenko is charged with mismanaging was legal.

The point here is that Mr. Yanukovych will have no chance of obtaining an association agreement with the E.U. — much less the path to full membership he seeks — if he insists on continuing the persecution of Ms. Tymoshenko. As Swedish Foreign Minister Carl Bildt put it in an op-ed published by the Moscow Times, “If the bizarre scenes now being witnessed in Kiev continue, even Ukraine’s closest friends in Europe will find it very difficult to make the case for a deepening of relations.” The Ukrainian leader must choose between Europe and autocracy; if he picks the latter, Ukrainians are not likely to remain passive.