By Jon Frandsen, Senior Editor March 17, 2008 Political issues that dominate elections -- the things that grab voters and help them decide how to vote -- often come out of nowhere to take on a life of their own. Who, for instance, would have placed much importance on gay marriage in the 2004 presidential race? Could something that people have given little thought to emerge as a leading voter concern this year? In a campaign as unpredictable as this one, you can almost count on it. Don't be terribly surprised if it's guns.Even with tragedies like the campus massacres at Virginia Tech last year and Northern Illinois in February, gun control has barely registered as a blip in the presidential debate. But that could change rapidly come June or July. That's when the Supreme Court is likely to issue its first ruling ever on how much protection the Constitution provides gun owners. The court hears arguments in the case, a 32-year-old law banning ownership of handguns in Washington D.C., on Tuesday and it usually doesn't issue its most controversial decisions until just before it adjourns in early summer.There's no way to anticipate how the court might rule. But it might not matter. One thing that seems likely -- although not guaranteed -- is that the justices won't interpret the "right to bear arms" clause of the Second Amendment as an absolute individual right that essentially disallows government regulation. And with nearly three-quarters of Americans believing the Constitution guarantees a right to gun ownership even though the court has never interpreted the Second Amendment that way, that is bound to energize gun rights voters. If the decision is relatively sweeping and sides with gun owners, the NRA and its supporters -- perhaps the largest special interest voting bloc of them all -- would begin pressing to eliminate existing gun control laws. And what better way to start than by pinning down presidential and congressional candidates. If the court allows restrictions by a narrow vote, those same groups would begin looking for ways to reverse the ruling -- largely by supporting a candidate most likely to nominate conservative Supreme Court justices friendlier to their cause.Guns as a decisive issue in this campaign could be bad news for Democrats. First, it could energize the GOP base in a year when many conservatives seem ready to sit on the sidelines. Second, it could shift attention away from issues that Democrats generally do well on. Democrats have long sought to neutralize the issue, allowing candidates in the South and West to embrace gun rights to survive while encouraging national candidates to stay away from it or voice generalized support for gun rights, especially for hunters. In fact, detailing personal handiness with guns has become a peculiar ritual of modern presidential campaigns -- all the better if you can be photographed traipsing through the fields with a shotgun at your side.But if guns gain traction as an issue and presidential and congressional candidates have to parse positions on specific gun policy -- Renew the assault weapons ban? Allow people to carry guns into National Parks? -- it would make it impossible for Democrats to get by with such blandishments. Congressional candidates could find themselves at odds with the top of their ticket. Barack Obama or Hillary Clinton would be struggling to find a position moderate enough to keep battleground and so-called purple states such as Ohio, Florida, Colorado and New Mexico in play without appearing to pander to the gun lobby. And they will be looking for every opportunity to change the subject to something less dicey. Like Iraq.