In 1992, James Carville popularized the adage "It's the economy, stupid." If the economy is ailing, people tend to vote against the party in the White House. That happened in the 1992 election. A recession that started in 1990 was officially over, but it didn't seem over to millions of Americans. They sent President George H.W. Bush into retirement. The question now is whether something similar will happen in 2016.

All eyes are on New Hampshire, but maybe we should be paying more attention to the economy. Along with the volatile stock market, recent indicators hint at a slowdown or recession. This could change the campaign's complexion once nominees are picked. Democrats could be thrown on the defensive. Their pitch to the middle class might be blunted, as Republicans blame President Barack Obama for the slump. Without a recession, it would be harder to attack Obama's policies.

Indisputably, recent economic releases have been downbeat. Consider. In the fourth quarter, the economy grew at a paltry annual rate of 0.7 percent. Personal spending in December was flat, as Americans saved more of their incomes. The manufacturing sector is weak, hurt by a strong dollar — which makes U.S. exports more expensive — and less oil exploration. Individually, none of these indicators is conclusive, but they are of a piece.