KIEV — Although the parties tied to Ukraine’s Orange Revolution look set to return to power following the latest national elections, the man who was the central figure of the 2004 mass protests appears to be increasingly losing power.

Viktor Yushchenko is now president, elected after the protests turned Ukraine’s politics upside-down, but the adoration of millions that he once claimed is little more than a memory. His party earned only about 16% of the parliamentary vote yesterday, according to partial results.

The party of his Orange Revolution enemy, Prime Minister Yanukovych, had about 30% of the vote, the partial results indicated.

The rising star, it appears, is Yulia Tymoshenko, a vivid, controversial figure whose bloc was leading with 33%. She was Mr. Yushchenko’s most fervent ally in the Orange Revolution, became his prime minister — and then a nemesis. Mr. Yushchenko fired her after just seven months in office.

Now she likely holds the key to Ukraine’s political future — and Mr. Yushchenko’s. If she allies with Mr. Yushchenko, their parties should have enough parliament seats to form a government; if she holds out, Mr. Yanukovych and sundry small allies could hammer together a coalition.

For Mr. Yushchenko, the alliance appears to be a last resort in maintaining at least some of his grip on power as he pushes reform and pro-Western policies. His popularity has suffered due to political infighting and disillusionment with endemic corruption, decrepit infrastructure and, for many Ukrainians, the struggle to make ends meet.

Constitutional changes he agreed to as part of a compromise during the 2004 protests handed many of the presidential powers to parliament, and Mr. Yushchenko has seen many of his policies and decrees challenged and blocked by Mr. Yanukovych.

His choice for foreign minister was not approved by parliament, his efforts to join NATO were put on hold, and even the chief prosecutor he fired initially refused to leave his office.

The early parliamentary election was in itself Mr. Yushchenko’s effort to stop what he called Mr. Yanukovych’s attempts to usurp power.

Mr. Yushchenko and his Orange allies weren’t able to put together a coalition after last year’s national elections. That gave Mr. Yanukovych room to move in — and the cohabitation resulted in months of a bitter stand-off that paralyzed the government.

This year, Mr. Yushchenko’s and Ms. Tymoshenko’s parties have pledged that if they’re able to put together enough seats for a governing coalition, the party with the most seats will name the prime minister and they’ll divide the Cabinet seats.

That could spell trouble for Mr. Yushchenko.

Ms. Tymoshenko, known for her steel will and hunger for power, is likely to try to get most of the key seats in the Cabinet for her party, pushing Mr. Yushchenko’s allies into less important positions.

Her party’s strong showing makes her a likely tough candidate in the 2009 presidential election.

Mr. Yushchenko can also expect trouble from Mr. Yanukovych.

The premier, who had fiercely resisted calling early elections, has hinted he will not bow out quietly if he fails to form a coalition. A grim-looking Mr. Yanukovych told reporters early today that his party was leading in the vote and had “carte blanche” to form a coalition.

With the election count underway, up to three smaller parties were likely to pass the 3% threshold and earn seats in the parliament. They could emerge as key players in coalition talks.

Mr. Yushchenko’s party’s dismal showing in yesterday’s vote isn’t surprising.

Mr. Yushchenko was poisoned with dioxin during the 2004 presidential election campaign, disfiguring his face. Suspicions of Russian involvement persist, partly because Mr. Yushchenko was running against Mr. Yanukovych, a Kremlin-backed candidate.

Sympathy and anger prompted throngs to stand in Independence Square chanting Mr. Yushchenko’s name in the freezing weather in 2004, but many feel he has let them down in the years since.

During those protests over election fraud, Mr. Yushchenko and Ms. Tymoshenko swore eternal loyalty to each other. But after the Supreme Court threw out election results declaring Mr. Yanukovych the winner and ordered a new vote — which Mr. Yushchenko won — he could only take seven months of Ms. Tymoshenko as his premier.

He fired her amid mutual accusations of corruption and incompetence, saying Ms. Tymoshenko often worked “with the aim of solving her problems” rather than the state’s.

Many supporters feel the Orange team has betrayed the “ideals” of the Orange Revolution, and Mr. Yushchenko’s sinking support has also played into Mr. Yanukovych’s hands.

Written off as the bad guy of the Orange Revolution, Mr. Yanukovych since has reinvented himself as a moderate who talks democracy and is cordial with both Russia and the West.

He has shored up his support base in the Russian-speaking east and south, and — capitalizing on widespread disillusionment in the Orange team — has sought to win over central and western regions traditionally loyal to the Orange forces by ushering in economic growth and raising wages and retirement pensions.