RALEIGH – It’s only a few weeks from Labor Day, which among other things will signify the beginning of the end – the “homestretch” – of the 2008 election cycle.

Political pros often counsel their candidates to wait until after Labor Day to begin heavy advertising buys and earned-media campaigns, on the grounds that voters pay little attention to politics during the summer. Experience tells us that, generally speaking, this is good advice – but only if you define your terms in a particular way.

First off, the “voters” they’re talking about aren’t all voters. They aren’t even most voters. According to decades of survey research, most American voters have their minds made up before the homestretch of the campaign. The American Enterprise Institute’s Political Report for July/August 2008 has a compilation of polls going back to the late 1940s. The share of voters who said they decided on their presidential preferences by the end of the national party conventions has varied over the years, but always remained above 50 percent.

Consider a couple of elections that bear some similarity to the 2008 cycle. Both in 1992 and in 2000, 54 percent said they made up their minds either before the primaries, during the primaries, or by the convention. In 1992, 25 percent of voters made up their minds in the last two weeks of the race, virtually indistinguishable from the 23 percent who said the same in 2000.

When consultants and pundits say that “the voters” don’t pay attention to politics until the fall, they mean to refer to independents and weakly leaning Democrats and Republicans. These are the voters who typically lack the most information about the candidates and issues. Their voting behavior can be sporadic. Ranging between a fifth and a third of the electorate, depending on the race, these swing voters don’t typically make their decisions based on some long checklist of issues or careful analysis of party platforms and candidate position papers.

The second point to make about the homestretch strategy is that it’s one of those general rules that, as a general rule, ought to be violated every now and then. Consultants of both parties have regaled me with stories about candidates who husbanded their resources, waited until the last moment, then spent gobs of money on ads that got lost in the September/October political miasma or ended up in less-attractive time slots that didn’t appear to deliver good bang for the buck. There are also cases where little-known candidates allowed their opponents to define their image early on, during the summer or even the spring primary season, and then tried futilely to re-introduce themselves to wary or uninterested voters in the fall.

Going back to the polling data, somewhere between 10 percent and 15 percent of voters in elections since 1992 said they made up their minds during the party conventions (the share used to be higher, in the high teens and 20s, back when network television commanded a larger share of the national audience and it was difficult not to catch some of the convention speeches on the tube). In elections decided by just a few percentage points, it’s obvious that mid-summer conventions present campaigns with a valuable opportunity to introduce their candidates to voters, solidify support among the party faithful, and develop themes that are going to be explored and reinforced in fall ads and campaign events.

That’s one reason why the Democrats and Republicans are each planning to spend tens of millions of dollars to put on their convention shows, even though the ratings won’t be stellar and the long succession of speeches can be monotonous. Some viewers will still get their first significant look at one of the candidates in August. Might as well try to make the candidates look as good as possible.

Hood is president of the John Locke Foundation.