In his regular radio address last Saturday, President Victor Yushchenko controversially stated that he would refuse to approve the Verkhovna Rada's Prime-Minister nomination until the VR attests the judges of the Constitutional Court.
Last December, Monitoring Committee of the Council of Europe Parliamentary Assembly (PACE) urged the Ukrainian Parliament to carry out its constitutional duty and renew the composition of the Constitutional Court of Ukraine without any further delay. [Some good further info in this particular link]
One of the reasons for the VR's foot-dragging was that it did not want the Constitutional court to assess the validity or otherwise of Law № 2222-VI on amendments to the Constitution of Ukraine, December 8, 2004, which the VR approved at that time. This law came about after negotiations between Kuchma, Yushchenko, and intermediaries, and was considered a 'trade-off', enabling the repeat of the second round Presidential elections to take place just after the Orange Revolution.
The law, which came into effect 1st January 2006, reduced the powers of incoming President Yushchenko, compared to those of his predecessor, Kuchma.
In December 2005, the Ukrainian National Commission on Democracy and Rule of Law had come to the conclusion that the Law № 2222-VI should be regarded as 'nullum ab initio', and therefore not be considered as the element of the current Ukrainian Constitution, according to a press release by Ukraine's Ministry of Justice .
As things stand at present, the President is the only state authority that can attempt to sort out the mess, and this perhaps explains Yushchenko's uncharacteristically forthright declaration last Saturday. He wants to regain those lost Presidential powers.