MSNBC host Chris Matthews cherry-picked poll data in order to support his misleading claim that Catholics have voted increasingly Republican since 1960. In fact, exit poll data indicates that Catholics are a swing constituency: In every presidential election since 1980, a majority or plurality of Catholics have voted for the candidate who won the popular vote, including Bill Clinton in 1992 and 1996 and Al Gore in 2000.
From the April 10 edition of the syndicated Chris Matthews Show:
MATTHEWS: Anyway, next up: coming home to America. Pact of faith. Ameri -- Republicans in America are shoring up the faithful into a phalanx of political power -- real power -- and it's working. Take a look at Catholics. They backed John F. Kennedy, of course, by huge margins. But Ronald Reagan got almost half of the Catholic vote in 1980, and George W. Bush got a majority, 52 percent, last year.
Here is the graphic Matthews displayed on-screen:
The graphic displayed poll data selectively in order to support Matthews' thesis that Catholic voters are trending Republican. It showed only the Catholic vote in 1960, 1980, and 2004. In fact, Matthews omitted data indicating that Democratic presidential candidates have fared well among Catholics in recent elections. Clinton won a plurality of Catholic voters in 1992 and a majority in 1996, and Gore won the Catholic vote in 2000. Democrats have won a larger percentage of Catholic votes than Republicans in three of the last six presidential elections, with Catholics voting for the winner of the popular vote each time, according to available reporting of exit polls:
A May 24, 2004, CBS News report goes back further, noting: "In that  election, and in every one since, Catholics have cast their votes for the popular vote winner, in numbers not too dissimilar from the public at large. In other words, Catholics have become a bellwether block -- as go Catholics, so goes the nation."