[JURIST] Ukrainian President Viktor Yushchenko [official website; BBC profile] on Thursday accepted the nomination [press release] of political rival Viktor Yanukovych [BBC profile] to serve as the country's prime minister, ending weeks of speculation that Yushchenko's rejection of the nomination would prompt a constitutional crisis [JURIST report]. Yanukovych's Party of the Regions [party website] won the most votes in March parliamentary elections, but did not secure an outright majority. The Party of the Regions formed a coalition Thursday with Yushchenko's Our Ukraine party [party website] and Yushchenko formally submitted Yanukovych's nomination to parliament. Ukraine's parliament, the Verkhovna Rada [official website], is expected to approve Yanukovych as prime minister on Friday.

Yushchenko and Yanukovych were fierce rivals in the 2004 presidential election [JURIST report], the results of which were invalidated by the country's Supreme Court [JURIST report] following fraud allegations. Yushchenko was sworn in as Ukraine's president [JURIST report] in January 2005 on the wings of the populist Orange Revolution [BBC timeline] after winning a re-vote. The latest political upheaval in Ukraine [JURIST news archive] was prompted by a parliamentary vote in January to dissolve the government [JURIST report], leading Yushchenko to criticize constitutional changes that have limited his authority and expanded parliamentary powers and to call for a new constitution [JURIST reports].

Yushchenko decided to accept Yanukovych as prime minister after the latter agreed to sign a National Unity Pact [press release] that preserves certain pro-Western elements of the president's agenda, including amending the Ukrainian Constitution [text] to include a "checks and balances" system and taking steps toward joining the European Union. Had Yushchenko refused to accept Yanukovych as prime minister, he would have been forced to dissolve parliament and call for new elections. The speaker of parliament had promised to disobey an order to dissolve parliament [Reuters report] and other members of parliament threatened to impeach Yushchenko [AP report] if new elections were called. BBC News has more.