ALBANY, N.Y. (AP) - New York's top court is weighing a constitutional challenge by state Senate Democrats who claim Republicans improperly used two different formulas to redraw the election map that created a 63rd Senate district upstate.

The Court of Appeals has expedited the case, hearing arguments Thursday after a trial-level judge found that using the different formulas to establish voting boundaries was "disturbing" but not unconstitutional.

Majority lawmakers in the Senate and Assembly struck a deal with Democratic Gov. Andrew Cuomo last month to approve new election maps that critics say were unfairly drawn to help protect their political power.

The Republicans hold a 32-30 majority in the Senate.

Democrats have a 2-to-1 voter enrollment advantage.

The new 63rd district would be west and south of Albany.