The presidential decree said nothing about what exactly "oath violation" by the judge in this case meant.
Pshenichny was appointed a Constitutional Court judge in January 2003 by then President Leonid Kuchma.
On April 26 the Ukrainian leader signed a second decree to dissolve parliament and call an early vote for June 24. The pro-governmental majority of parliamentarians contested the decision and filed an appeal to the Constitutional Court, which has yet to make a decision.
On April 25, Pshenichny, while considering the constitutionality of Yushchenko's April 2 decree dissolving parliament, said the president demanded that a transcript of the court session be given to him, but added that Yushchenko is not entitled to demand that.
The political crisis in Ukraine was triggered by the defection of 11 pro-presidential lawmakers to the majority parliamentary coalition backing Prime Minister Viktor Yanukovych in late March.
Thousands of Yanukovych and Yushchenko backers have been rallying in central Kiev, bringing back memories of mass protests that swept Yushchenko to power after Yanukovych lost the presidential poll over vote rigging accusations.