States can draw electoral maps for partisan gain, but not if it dilutes the power of voters of color, courts have found.

Democratic lawmakers tried to build a case Friday that Republicans in Texas have engineered a rushed and unfair process for redrawing the state's congressional districts in response to a push by President Donald Trump to win more GOP seats that Democrats fear will spread to other states.

The Texas House Select Committee on Congressional Redistricting heard testimony Friday on a proposed map that would redraw 37 of the state's 38 congressional districts, with changes primarily focused on five districts drawn for partisan Republican advantage.