a somewhat dated article - but a good explanation of you constitutional right to vote according to a couple of supreme court decisions:

Beyond the Voting Rights Act:

"...In its 2000 ruling, Alexander v Mineta, the Court decided the 600,000 or so (mostly black) residents of Washington D.C. have no legal recourse for their complete lack of voting representation in Congress (they have one “representative” in the House who can speak, but cannot vote). The Court affirmed the district court's interpretation that our Constitution "does not protect the right of all citizens to vote, but rather the right of all qualified citizens to vote.” And it's state legislatures that wield the power to decide who is “qualified.”

As a result, voting is not a right, but a privilege granted or withheld at the discretion of local and state governments..."

have there been any decisions to overturn those mentioned in the 2005 article?