Pope Benedict XVI ascends to power at a tumultuous time for his church in American politics: Catholic voters, long overwhelmingly Democratic, have become a critical swing vote. Republicans have become increasingly successful at winning the support of more traditional Catholics by appealing to what President Bush calls the "culture of life" issues, including abortion, euthanasia and research on embryonic stem cells. Mr. Bush carried 56 percent of the white Catholic vote in 2004, up from 51 percent in 2000 - a formidable part of his conservative coalition.
This voting trend is longstanding and would have existed and continued even if John Paul had survived. But the point is that Ratzinger headed the Congregation for the Doctrine of the Faith, which backed American bishops who "have become more assertive in urging their congregations to vote in accord with Catholic teachings on those issues" and who have "chastis[ed] Catholic officials who disagree, in a few cases by threatening to deny them Communion." So there's a prediction that Catholic voter will keep feeling the need to vote based on "culture of life" values.
There is also an effect on candidates themselves. The article, written by Robin Toner, clearly seems to favor the John F. Kennedy approach to Catholicism and politics: "I do not speak for my church on public matters, and the church does not speak for me." It worked for Kennedy (who had to battle anti-Catholic prejudice), but John Kerry had difficulty using the same move. He had difficulty for any number of reasons: he didn't need to overcome an initial aversion to a Catholic president, and he had to operate in a political field where personal moral questions have become central.
The gist of the article is that Benedict will energize American bishops to directly criticize Catholic candidates who don't adopt the complete set of orthodox Catholic beliefs, which will make it very hard on Democratic candidates. But there is no direct quote saying that. The closest of the many quotes is this one:
"I hate to pre-judge, but based on the record I would say Ratzinger is a very serious Catholic and he's going to say things like, 'Beware of falsehood in advertising,' " said Michael Novak, an expert on the Vatican at the American Enterprise Institute. "If you say you're a Catholic, be a Catholic."