As everyone knows by now, in the wake of the massacre at the Emanuel AME Church in Charleston, South Carolina lasted week, allegedly perpetrated by a racist, Dylann Roof, there have been renewed calls to remove the Confederate flag from state grounds.

Among Republicans, those calls have come from prominent lawmakers from South Carolina, most especially  Governor Nikki Haley, who is playing a significant role in transforming this debate. Among those running (or are likely soon to run) for president, Jeb Bush and Rick Perry signaled early on they wanted the flag taken down. Scott Walker, after days of hesitation, then followed. So, now, has Rand Paul. (Here’s a good score card of who stands where.)

Yet several others – including Ted Cruz, Rick Santorum, Mike Huckabee, Bobby Jindal, Ben Carson and Marco Rubio – have said it’s a decision best left to South Carolinians. They have so far remained basically neutral when it comes to rendering a judgment on the Confederate flag.

They shouldn’t. In politics there are a lot of hard calls; this isn’t one of them.

As the old arguments in favor of allowing the Confederate flag to fly on state grounds crumble before our eyes — they already seem bizarrely antiquated — it’s worth recapitulating the reasons the debate has changed in such a decisive way. The first one has to do with the history of the Confederate flag. For all the talk from defenders of the flag who insist otherwise, it was a symbol of slavery, white supremacy, and the dissolution of the Union. The flag was fundamentally about hate, not heritage; about subjugation, not Southern ancestry. There is a reason white supremacist groups embrace the Confederate flag as their symbol, and it doesn’t have to do with its aesthetic appeal.

The second reason has to do with the history of the Republican Party. It was founded in the 1850s by anti-slavery activists and in opposition to the Kansas-Nebraska Act. Its slogan in 1856 was “free labor, free land, free men.” The first Republican president, Abraham Lincoln, was America’s “great emancipator” who freed the slaves. So the Confederate flag was never a symbol associated with the Republican Party – including in South Carolina, where the flag was first flown over the statehouse in 1962, at the request of Democrats in the state like Governor Fritz Hollings and Representative John A. May. Yet the Republican Party has somehow found a way to get itself attached to this toxic symbol of division and repression.

The third reason it’s an obvious decision to call for the Confederate flag to come down is political. Among those who have a reaction to the flag, more than three times as many  say they have a negative reaction as a positive reaction.

Beyond that, the United States is rapidly changing. It’s becoming increasingly non-white. One reason Republicans are consistently losing presidential elections is that they are doing dismally among minorities. For example, in 2012 the Republican nominee won just 17 percent of nonwhite voters. (The white share of the eligible voting population has been dropping by about two points every four years, and next year minorities may make up a record 30 percent of the vote.) Republicans are unlikely to endear themselves with this rising demographic if they refuse to take a stand against flying the Confederate flag.

There is, finally, the issue of civic comity. The Confederate flag not only represents the ugliest part of our history; it is a symbol that makes many Americans feel like outsiders in their own land, alienated from their fellow citizens. Not giving that kind of offense is a basic commitment of democratic life.

But there are still holdouts. In his appearance on NBC’s Meet the Press on Sunday, presidential hopeful Mike Huckabee, who in 2008 finished second to John McCain in the Republican primaries delegate count, claimed the Confederate flag is not an issue for someone running for president. Governor Huckabee told host Chuck Todd, “if you can point me to an article and section of the Constitution in which a United States president ought to weigh in on what states use as symbols, then please refresh my memory on that.” Set aside the fact that people running for president weigh in on matters beyond the scope of the Constitution all the time. (A few weeks ago Huckabee spoke out on the matter of Caitlyn Jenner’s sex-change operation, an issue on which the Founders were silent.) It seemed entirely lost on Governor Huckabee that the Confederate flag was the symbol of a rebellion against and violent assault on the very Constitution Mr. Huckabee invoked.

To their credit, in just a few days a rapidly growing number of Republicans – Governor Haley and the presidential candidates I mentioned, RNC chairman Reince Priebus, Senator Majority Leader Mitch McConnell, 2012 presidential nominee Mitt Romney and others, with many more to follow – have urged the Confederate flag be taken down. We’re clearly at a much-welcomed tipping point. The tragic event in Charleston, and the extraordinary grace demonstrated by the families of the victims, seems to have allowed long-standing arguments to gain traction in ways they never had before. And for those Republicans who are still agnostic or ambivalent when speaking on this issue, they need not be. They should view this as an opportunity to finally put to rest an issue that has bedeviled their party; to stand four-square against a symbol of cruelty and, in so doing, remind voters that theirs is the proud Party of Lincoln.