OSV: What an Obama presidency means for Catholics by Russell Shaw
Read this article. It is an excellent assessment of what stands before us.
In a nutshell, the problem is this: While some Catholics who voted for Obama no doubt agonized about backing a strongly pro-abortion candidate, millions of others evidently voted this way without any qualms. According to exit polls, McCain got just over half of white Catholics' votes, down 13 percent from George W. Bush's showing in 2004. Obama's gain among these Catholics was said to be mainly among those who don't attend Mass weekly.
What can the bishops do? Clearly, they aren't of a mind directly to oppose pro-abortion candidates in the future -- for fear of losing the Church's tax-exempt status, because they believe it would conflict with their role as religious teachers, and because doing that might actually benefit the candidates they opposed.
But the evidence of 2008 is that broad consensus statements from the U.S. Conference of Catholic Bishops like this year's document called "Faithful Citizenship" are of questionable value. Indeed, some pro-Obama Catholics actually mined "Faithful Citizenship" to find arguments in support of their choice.