The two red-hot issues fused by the District of Columbia v. Heller case — guns and judges — are two of the most divisive in American politics.

D.C. v. Heller could become one of the most important cases in American history, with profound political and policy implications.

The case will directly affect 90 million American gun owners. Whether they have a constitutional right to own guns immediately makes their ownership either a protected right or merely a privilege that the government can restrict at will. Either way everyone else in our society is indirectly affected.

Gun bans fall particularly heavily on women, minorities, the elderly, and the disabled who own guns for self defense purposes. Though stereotypical gun owners are white adult males in the prime of life, the reality is that these are the people who need guns the least. Most people are more likely to be a victim of violent crime, and thus have a greater need for a tool that neutralizes any would-be criminal’s greater size, strength, or speed.

The short-term political impact of Heller might turn the 2008 presidential election. Either Senators Clinton or Obama would the most anti-gun Democrat nominee in American history. The Second Amendment is a pivotal issue in a half-dozen swing states, and other swing states have smaller gun votes, but gun owners could easily tip those states in a close election.

Heller will heat up twice during the presidential campaign, first when the case is argued in March and second when the Court hands down its decision, most likely in June. Gun owners will either be emboldened, pressing forward for policies recognizing their rights, or outraged that an activist Court has denied them their cherished right, holding rallies, and taking to the streets. Either way, gun rights could dominate the news.

In addition to guns, this evaluation of the party nominees’ records is true for federal judicial nominations. Heller will fuse the issues of guns and judges in America. The four conservative justices — Justices Roberts, Scalia, Thomas, and Alito — are expected to support an individual’s right. Most or all of the liberal justices — Justices Stevens, Ginsburg, Souter, and Breyer — will oppose an individual’s right. That leaves Justice Kennedy — the only moderate on the Court — as the swing vote who could decide the meaning of the Second Amendment.

It cannot be overstated how much Heller will make judicial nominations a campaign issue for tens of millions of gun owners, millions of whom usually vote Democrat. With John McCain naming Justices Roberts and Alito as models of who he would nominate to the Supreme Court and Senators Obama and Clinton both naming Justice Ginsburg as their model, it will be impossible to be pro-gun yet fight for a liberal Supreme Court at the same time. This also will be true for Senate seats as well, where pro-gun states will demand that their U.S. senators support nominees who will uphold their gun rights.

Heller’s impact could go well beyond Election Day. It could actually have a lasting impact on our culture itself as one of the cases that reshapes the national dialogue.

Take the example of Everson v. Board of Education. This 1947 case created the doctrine of separation between church and state, launching 60 years of the radical secularization of our culture and an all-out war against people of faith, especially conservative Christians. What’s important about Everson is that the religious people actually won that case, but the rule the Court proclaimed in it has systematically stripped religion of its social influence ever since. Though the idea of separating church and state was almost unheard of in 1947, it has now become a widely accepted concept in our culture. That is the power of a landmark Supreme Court case.

There have been a handful of cases that have shaped America. Roe v. Wade, Dred Scott, Plessy v. Ferguson, Brown v. Board, and Marbury v. Madison are more than just history book entries; they actually changed the nation. For good or ill, District of Columbia v. Heller might join that list. It could become the Roe v. Wade of gun ownership.

And Heller is just the beginning. There will be more Second Amendment cases. If the Court finds that the Second Amendment guarantees an individual’s right to own firearms, 20 years of major cases will follow, fleshing out the contours of this right.

District of Columbia v. Heller is in the hands and minds of nine judges who sit on the highest court in the land and whose majority opinion could change the course of American history, one way or the other. As with abortion, affirmative action, and gay rights, the biggest battles over gun rights will hereafter be fought not in Congress or state legislatures but in the courts.

This is Part II of a two-part series. Mr. Blackwell is a fellow at the American Civil Rights Union. Ms. Froman was the president of the NRA.