By: Judy Woodruff

A boy watches TV screens at an electronics shop outside Washington, D.C. Photo courtesy NICHOLAS KAMM/AFP/Getty Images

I'm often tempted in covering political campaigns to agree with voters who say they are fed up with negative advertising and the constant criticisms that candidates level at one another. Living in Washington, D.C., I've been treated lately to some of the TV spots aimed at persuadable voters in next door Northern Virginia. They remind me of what voters who live in the most hotly contested battleground states - like Florida and Ohio - live with practically every election year.

There's no question that negative campaigning seems over the top these days and that the Supreme Court ruling in the Citizens United case enabled an even greater torrent of charges and counter-charges to fly through the airwaves, paid for by so-called super PACs, outside groups supporting the candidates. I've done my share of deploring the ugly tone many of these ads take.

What's just as disconcerting is the sort of analysis done recently by Democratic strategist Paul Begala, who calculated that the roughly $2 billion that will be spent this year by the Obama and Romney campaigns and their outside supporters, is aimed at just 1/320th of the U.S. population - the 916,643 people he calculated who make up the undecided vote in six critical swing states: Virginia, Florida, Ohio, Iowa, New Mexico and Colorado. (Begala guessed that Obama and Romney could count on 48 percent of the vote in these states, leaving just 4 percent of the electorate truly "persuadable.") In a clever conclusion, he suggests the candidates consider sending each undecided voter his or her share of the loot spent on ads - which would come out to $2,181.87 - money he believes the voters would prefer instead.

Begala may be on to something. But in the meantime, since the campaigns believe it's worth $2 billion or more to try to influence us, since they believe there's that much and a lot more at stake in the election, I humbly suggest it's worth our time to listen. Rather than turning off the TV, all of those who have time to watch the ads - decided and undecided voters - may want to pay careful attention to these spots, and hold them up to scrutiny. Ask yourself questions after you see a critical ad on television, or hear one on the radio: What exactly is the opponent alleging, if it's a negative spot? Does it have any ring of truth? What's the candidate's motive in airing this ad? Why did his campaign pay to air it at this time, next to this program? Whom is he trying to reach? What is he trying to get us to think about the other candidate?

Most of us don't have time to fact-check a spot, but if possible, it's smart to keep an eye out for fact-checking done by news reporters we trust. If it turns out the ad is misleading or an exaggeration in any way, what does that make us think about the candidate who ran it?

All of us know there are huge stakes in every election, arguably more in this one than usual, because of the fundamentally different philosophies the candidates have about the role of government. Tax and spending policies, Supreme Court and other federal judiciary appointments, the decision to wage war, to name a few. Elections matter. For those of us who have the time, (clearly, many of us are too busy with jobs or family), dissecting the charges candidates fling at each other is an exercise well worth engaging in. At least for the first 25 times the spot airs. After that, you get a reprieve.