by Andrew Kohut, President, Pew Research Center
Special to the New York Times

Generally, the issues matter most in voters’ judgments about presidential candidates, but personality, character and values are not far behind. This is especially the case in the primaries where differences between candidates of the same party tend to be modest.

Fully 62% of Republicans said they would be less willing to vote for a candidate who had committed adultery. For example, leadership and personal qualities were more important to Republican voters in New Hampshire in 2008 than positions on issues. And a victorious John McCain bested Mitt Romney from neighboring Massachusetts by a huge margin on the personal dimension — though there is no one way that voters size up the personal dimension.

In past Pew Research Center surveys, voters said that honesty is the single most important thing they wanted to know about a candidate. However, significant numbers also think that it is important to learn about a candidate’s openness, personal background and the candidate’s spouse.

With regard to a candidate’s personal life, divorce is not much of a consideration — it has been a long time since Gov. Nelson Rockefeller’s presidential aspirations were derailed by divorce. In 2007, just 9% of voters said that they would be less willing to vote for a divorced candidate. But adultery is another matter; as many as 39% said they would be less willing to vote for a candidate who had had an extra-marital affair.

Republicans are especially reluctant to vote for a candidate who has had an affair. Fully 62%  said they are less likely to do so. Many fewer Democrats, having stood by President Clinton during the Lewinsky scandal, drew that line. Only 25% said such a candidate would likely lose their vote.

As for spouses, in recent years first ladies have run ahead of their husbands in public opinion polls. Laura Bush was more popular than George W. Bush throughout much of his presidency. And now we see Michelle Obama with a higher favorability rating than the president’s. In fact, majorities of various Republican voting blocs, except for staunch conservatives, have a positive reaction to the first lady.

However, in some instances, public opinions of some first ladies have paralleled negative views of their husbands at difficult times. Nancy Reagan was criticized for a lavish lifestyle during the “Reagan recession,” and Hillary Clinton drew substantial criticism as an architect of a unpopular health care reform plan.

Read other debaters’ takes on how much voters care about a politician’s marital history and family life at the New York TimesRoom for Debate discussion: “When Private Lives Become Public.”