The hierarchy of the American Roman Catholic Church has embraced the Republican Party in this presidential election because of one issue: abortion. And the GOP has bent over backwards to cater to the bishops — mostly grey-haired white men with a skewed view of the world.

Mitt Romney, the presumptive Republican presidential nominee, has benefitted from the alliance. But with Romney’s announcement Saturday that Wisconsin Congressman Paul Ryan will be his vice presidential running mate, the Catholic Church’s leaders are in a bind.

Ryan, a seven-term congressman and chairman of the House Budget Committee, is the architect of a budget balancing plan that benefits the rich and punishes the poor. The bishops have harshly criticized the Ryan plan as hurting the most vulnerable of Americans.

It will be interesting to see whether the bishops are willing to take on the Romney-Ryan team on this important social justice issue — the way that a group of outspoken, dedicated American nuns have been doing during their national tour. They have been harshly criticized by the Vatican and have raised the ire of some American Catholic leaders. But the nuns have been undaunted by the criticism, arguing that a political agenda that hurts those who are already struggling to survive is not a Christian value.

The Romney-Ryan ticket has pleased the ultra conservative in the Republican Party, but it remains to be seen whether the Bible thumpers, who are suspicious of Mormons and Catholics, will overcome their religious bigotry.

Meanwhile, the Catholic bishops have a decision to make: Ignore their misgivings about the Ryan budget just because of the abortion issue, or stand on principle.