The Washington Post / By Albert R. Hunt

April 23 (Bloomberg) -- This is expected to be a close U.S. presidential election and there’s a general consensus in both camps about who, to paraphrase former President George W. Bush, the “deciders” will be.

The swing groups are constituencies that went for Barack Obama in 2008 and voted Republican in the 2010 congressional elections, or voting blocs in which the premium is passion not preference.

-- Married women with children. There is a gender gap, and much of the focus now is on Mitt Romney and females. In 2008, Obama carried the women’s vote by 13 points. A more closely contested demographic, however, are married women with children, who are less Democratic than most other women. They account for about 15 percent of the electorate and went for Obama 51 percent to 47 percent four years ago, but swung to Republicans in the midterm elections.

“This is a group that Romney ought to carry,” says Whit Ayres, a Republican poll taker.

The issue of not getting the economy on track is of particular importance to married women. Anecdotal evidence suggests that some issues such as abortion and contraception don’t resonate as much. One concern they do have is education; this debate hasn’t yet begun in the campaign and is an area where the Obama forces say they have the advantage.

-- Suburban independents: This group made up about 12 percent of the electorate in 2008 and went for Obama by 7 percentage points, about the same proportion as his overall margin of victory. In the 2010 House races, Republicans carried these suburbanites by almost 25 points, a huge turnaround.

These voters vary slightly from the general electorate in several different ways: They are a little bit more male, more middle-upper income, more college-educated, more likely to be investors and slightly more middle-aged.

-- Catholics who aren’t regular churchgoers: Catholics, who account for a little more than a quarter of the electorate, are closely divided between those who regularly attend church and those who don’t. The most observant tend to be the most Republican and most responsive to their bishops’ criticisms of the president.

“John McCain carried these active Catholics last time, though not as much as George W. Bush did in 2004,” says Steven Wagner, who runs an opinion-research company and provided counsel on the Catholic vote to Karl Rove, Bush’s political adviser. “If McCain had matched Bush with active Catholics, it would have made a difference in several states.”

There’s a much smaller group of Latino and African-American Catholics who are expected to vote decisively Democratic. The swing group is comprised of white Catholics who aren’t regular churchgoers and not as in tune with the religious leadership. Their vote is likely to be affected by whether they are swayed by the criticism that Obama’s health-care policies have infringed upon religious liberties, as the bishops charge, or whether they believe Republicans are trying to limit the use of contraceptives (which most Catholics use).