While Justice Kennedy has written some pretty great opinions lately, without the presence of Justice O'Connor, Kennedy has been left to steer the court.
The results have not been pretty: 4-1-4 decisions, vague concurring opinions, multipart multi-split opinions and generally bad law all around.
Why are the police able to turn knock-and-announce warrants into no-knocks at their discretion? Why has the Clean Water Act been, um watered down? Why has mid-decade re-redistricting been upheld? Because Kennedy is the lone swing vote.
Vieth v. Jubilander was also a terrible case, and these are hard issues, but allowing redistricting purely because the legislature changes political hands sets an awful precedent. This is in effect makes the U.S. House of Representatives the pre-Seventeenth Amendment U.S. Senate-- a federal legislative body whose members are chosen at the whim of each state legislature. The House will now represent the majority party in their home state's state house (and governor's mansion), and not the people of their district. With advances in statistical analysis and computer programming is it possible to create districts which virtually lock in a seat for a particular party.
The Framers of the Constitution intended the House to be the more representative body, which is why they made it larger, based on population, and gave it the power to originate spending and tax bills, the power to impeach, and the power to choose the president in the case of an electoral college tie/plurality. The Senate was supposed to be the more deliberative, tempered body (the saucer to cool the hot coffee of the House's cup) filled with more learned, wise men [now a few women], which is why they had the power to ratify treaties, advise and consent on presidential appointments, and vote to remove the President or Supreme Court Justices from office.
Gerrymandering has turned this all on its head. I am sure that the Founders were political and believed in Gerrymandering (after all, it started with the first Congress) but I highly doubt they ever dreamed mapmakers would ever wield the precision and predictability they possess. If they had known where it all would lead, I doubt they would have approved of such counter-majoritarian abilities.
Maybe the court looked the other way because Democrats in 1990 redistricted Texas overly favorably to their cause and the DeLay Gerrymander was just a wing in the opposite direction that made the state Congressional delegation match the statewide voting percentages. But now other states will be emboldened to reredistrict not just to "correct and injustice" but to counter the will of the people. The very fact that elected officials are now beholden more to mapmakers and party bosses than the electorate violates the spirit, and I believe the letter of the Constitution.