Virginia voters will get to cast ballots on a congressional redistricting plan that could help Democrats in this year's midterm elections. On Friday, the Virginia Supreme Court said an April 21 referendum can go forward while it considers a legal challenge to the redistricting plan. A lower court ruled last month that the proposed constitutional amendment allowing mid-decade redistricting was invalid because of the way state lawmakers passed it. Democrats appealed. The Supreme Court agreed to hear the case. But it wont be resolved before the April referendum. The Virginia plan is part of a national redistricting battle between some Republican and Democratic states.