Does a candidate’s age matter in presidential elections? It’s less relevant than you might think.

A Pew poll released last week asked voters how likely they would be to support a presidential candidate with various traits or experiences, like being a governor, a Catholic or a woman. Although these might seem like important factors in how people make up their minds, voters often seem to work backward, rationalizing their views of the likely contenders rather than expressing a strong preference for a particular type of candidate.

Before the 2008 presidential campaign, for example, Democrats were much more likely to raise concerns about electing an older presidential candidate. A February 2007 Pew poll showed, for instance, that 60 percent of Democrats said they would be less likely to support presidential candidates in their 70s — far more than Republicans (42 percent) and independents (43 percent).

These differences were presumably related to the prospects of John McCain, a top Republican presidential contender who would have been 72 when he took office. It’s not surprising, then, that 36 percent of Democrats said Mr. McCain was too old to be president in a September 2008 Pew poll compared with 21 percent of independents and 11 percent of Republicans.