Perhaps the most-hyped Supreme Court decision of all-time may have little impact on who wins the presidential race.

Why not? Because health care is not a top-of-mind issue with most voters, particularly the undecided who will decide if Barack Obama or Mitt Romney wins the election. Polls consistently show the economy as by far the most important issue to most Americans. In a recent Gallup survey, 68 percent of people cited economic issues as the biggest challenges the country is facing today, while only 6 percent named health care.

Those polls suggest a slim majority of Americans oppose the law, while only about 40 percent back it. But many of these same surveys show Obama ahead, suggesting there are voters who don’t agree with the law but still support the president, and voters who oppose the law but won’t back Romney simply on that basis.

According to a recent Pew Research Center poll, more than 80 percent of Republicans oppose the law, while more than 70 percent of Democrats support it, unsurprising numbers in an increasingly-partisan country. In short, for most people in America, their view on the health care law is determined by which party they belong to.

That Pew survey showed 55 percent of independents opposed the law, while just 36 percent support it, a potential problem for the president. But  Pew survey has showed Obama ahead of Romney by four points in the race.

And the Supreme Court decision ruling is unlikely to shift how Americans view the law or President Obama in a dramatic way. While many Americans don’t know the details of the law, it was extensively covered in 2009 and 2010 by the press, and people have strongly held views on whether they like it or not. The part of the law that is widely expected to be struck down, the individual mandate, is already unpopular with the majority of voters.

Views on the Supreme Court decision are likely to track along partisan lines, with Democrats praising parts of the opinion that support Obama’s views and Republicans extolling the court when it takes on the president.

What will change after Thursday? The decision will shift how the two candidates approach the issue. Obama, who has spent little time on the campaign trail discussing health care, may now press Romney on how and if he will cover Americans who suffer  from chronic illnesses, who may have trouble getting insurance if the mandate is struck down.

Romney, who has long criticized the law, is likely to attack Obama, who was a constitutional law professor, for spending a year pushing a provision the Supreme Court then ruled was unconstitutional.

But like Obama’s decision to embrace gay marriage, which produced little change in the polls, the health care ruling will play less of a role in determining who wins the presidential race than the monthly reports on unemployment.

Follow Perry Bacon Jr. on Twitter at @perrybaconjr