WASHINGTON—Texas’ congressional and legislative maps appeared no closer to clarity following Supreme Court arguments Tuesday that went into overtime in addressing claims of racial gerrymandering stemming from Republicans’ redesign after the 2010 census.

Last year, a federal court in Texas ordered Gov. Greg Abbott to call a special legislative session to redraw political maps it found were tainted by discrimination against Hispanics and blacks. The Supreme Court, voting 5-4 along conservative-liberal lines, blocked implementation...