There's a scanned PDF version of the book
"The Moral Obligation of Voting" by Fr. Titus Cranny (Imprimatur 1952) available online, abridged:
http://www.novusordowatch.org/cranny-abridged.pdfIt outlines and explains the traditional Catholic position on voting in democratic elections, esp. in the United States. Very interesting. It talks about a lot of the issues we face, such as voting for a lesser evil, voting in primaries, giving good example vs. giving scandal, what if only bad candidates are running, etc.