Josh Gerstein for Politico:

Justice Antonin Scalia’s death is certain to have an impact on the political debate in this year’s elections, but it could also have a far more direct effect on the elections themselves.
There are numerous challenges to Republican-led congressional redistricting plans and new voter ID laws likely to come under Supreme Court scrutiny. Scalia had been a reliable vote for allowing such redistricting plans and voting rules.

A new justice nominated by President Barack Obama and confirmed by the Senate would almost certainly shift the court in the direction of stricter voting rights enforcement and a greater willingness to take account of race when considering redistricting and election law matters
But the more likely scenario in the near term — deadlock over Scalia’s replacement — could have a similar effect by leaving the court less likely to come up with the five votes required to set precedents on such matters and to issue emergency stays in challenges to last-minute voter ID and election-law changes coming up from lower courts.