ALBANY, N.Y. (AP) — Democrats in the New York Legislature on Monday rejected a congressional map drawn by the state’s bipartisan redistricting commission, setting the stage for the party to craft lines that help Democrats in battleground House races that could determine control of Congress.

The Democratic-dominated state Legislature will now have to submit and approve a new set of congressional lines, which is expected in the coming days. Republicans have already begun to float a potential legal challenge.

Congressional races in New York, particularly suburban contests, are expected determine which party controls the House after the November elections, adding major significance to even the slightest tweaks in how districts are drawn.

The move came about two weeks after the state’s Independent Redistricting Commission approved a map that would have helped Democrats in two districts and a Republican in one, but left most of the other lines in place.

Democrats had panned the commission’s map after its release, arguing it split up so-called communities of interest — though many expected Democrats to kill the proposal so they could draft maps that were more advantageous for the party’s congressional candidates.