KIEV, Feb. 1 – Ukrainian lawmakers on Tuesday changed the constitution to postpone the next parliamentary election by 18 months and the next presidential election by two months, benefiting President Viktor Yanukovych and his allies.

The changes were approved by 310 lawmakers in the 450-seat Parliament, underscoring the overwhelming legislative control that Yanukovych has assembled in the year since becoming president.

The next parliamentary election will now take place on Oct. 29, 2012, a delay from March 27, 2011, and the next presidential election will be held on March 29, 2015, a delay from January 2015.

The changes are a setback for opposition leaders, such as former prime minister Yulia Tymoshenko, former parliamentary speaker Arseniy Yatseniuk and Oleh Tiahnybok, the leader of nationalist Svoboda party, who have been seeking to increase their political power as soon as in March.

“The lawmakers exceeded their authority and in spite of the will of the voters had in fact usurped the legislative branch of power and had eventually undermined its legitimacy,” Svoboda said in a statement. “The Rada turned into a collective Regions Party.”

“That’s why it is the Regions Party and its leaders that bear responsibility for the usurpation of power and the destruction of the legislative institution in Ukraine,” Svoboda said. “Beginning today, the current Parliament has lost its legality in the eyes of Ukrainian society.”

This is the second time that Yanukovych has changed the constitution over the past four months.

On Oct. 1, 2010 the Constitutional Court, which almost entirely consists of Yanukovych allies, cancelled 2004 constitutional amendments to reinstate the 1996 constitution that gives Yanukovych huge powers, such as the ability to fire the prime minister and the ability to appoint and dismiss any minister.

The 1996 constitution, however, set the next parliamentary election on March 27, 2011. The opposition leaders hoped to use this upcoming election as a chance to increase their clout in Parliament and to oppose the police of Yanukovych.

Opposition groups indicated they may challenge the vote since at least 25 lawmakers among those 310 that voted to support the change of the constitution appeared to be absent from Parliament.

The constitution requires that every lawmaker personally votes in Parliament.

“This is one more time that Parliament, while voting to change the constitution, has been violating the same constitution,” Serhiy Sobolev, a member of the Tymoshenko group in Parliament, said. “At least 25 lawmakers that [voted to approve the amendments] were absent today.” (tl/ez)