THE BRONX - Democratic state senators Pedro Espada Jr. and Hiram Monserrate, who voted with the GOP to force their own party out of power Monday, say they did not switch sides, but rather made a step forward toward creating a bipartisan coalition.

Democrats, however, call the move a coup that could change the leadership structure in Albany. The Republican takeover of the state Senate spells out a promotion for Espada, a Bronx Democrat who will now preside over the Senate.

Beginning Wednesday, the GOP will have two weeks before the end of the session to decide on several key issues, including mayoral control of New York City public schools, gay marriage rights, ethics reform and changes to city rent laws.

The Democrats have vowed to challenge the power shift in court. In the meantime, Gov. David Paterson says although there is nothing he can do about the Republican coup, he is committed to working with whoever is in power.