On Thursday, a nation that has long been one of our strongest allies will decide whether to become the first nation to leave the 28-member European Union. Great Britain’s choice in the so-called “Brexit” referendum will undoubtedly have far-reaching implications, regardless of the outcome. And with the latest polls showing a tight split, the outcome remains unpredictable.

Exactly what is at stake, though, depends on who you ask. Some “Brexiteers” believe an EU exit is the only way to maintain sovereignty and preserve constitutional democracy, while some “Remain” advocates warn that separation would remove a critical balance the UK brings to the EU.

The Wall Street Journal editorial board is among those advocating Britain stay. The editors argue that the American interest of a “free and prosperous Europe … is best served with Britain as part of the European Union to balance France and Germany. The British look west across the Atlantic more than continentals, and the Brits have largely been a voice of reason in Europe’s councils.”

Additionally, the pro-Remain side notes that a newly separated Britain would have to renegotiate individual trade treaties with the rest of the world, as it would no longer benefit from EU agreements. “For all of its faults,” the Journal notes, “the EU has often been a stronger voice for free trade than its member nations.”

On the opposite side, however, are those who believe Britain’s national sovereignty and, indeed, her constitutional democracy are at risk unless she exits. National Review, for example, cast the choice as “whether to remain a self-governing democracy or to ratify their absorption into an undemocratic European polity.”

The Brexiteers point to an unaccountable European Commission that never stands for re-election, a body of EU law that surpasses national laws, and steady tension between British and EU interests. “In exchange for its democratic sovereignty,” National Review notes, “the EU offers Britain not power but a one-twenty-eighth share of collective decision-making with countries whose interests are badly aligned with those of the Brits. That is why Britain is continually outvoted in Brussels even when its major national interests are at stake.”

Indeed, the Journal also notes, “Too often, the EU’s grandees have ignored national referenda to impose their vision of closer political union.”

Ironically, one policy example both sides use to support their claim is immigration. EU rules dictate that anyone with an EU-nation passport can live in the UK, raising concerns that Britain’s borders are not truly her own. Remain advocates, however, claim Britain needs the influx of European immigrants to sustain her economy. Hence, they claim EU membership ultimately benefits Britain.

Of course, the issue in all of this is not truly which policies Britain should or should not embrace but whether those decisions should be made in London or in Brussels.

Unfortunately, Barack Obama seems to think the Oval Office is an alternate location from which to govern the UK. During a visit to Britain, this past spring, Obama clearly conveyed his choice that Britain stay in the EU, and issued a backhanded threat that if Brexit became reality, Britain would be pushed to the “back of the queue” for trade deals. “I think it’s fair to say that maybe at some point down the line there might be a U.K.-U.S. trade agreement,” Obama said. “But it’s not going to happen any time soon because our focus is negotiating with a big bloc, the European Union, to get a trade agreement done.”

Of course, this threat is ridiculous. As The Daily Signal points out, the U.S. “already ha[s] trade agreements with Jordan and Columbia, which are strategically important, but not major trading partners.” Why would we not place a high priority on trade with a very important ally?

On the congressional front, several House members sent Obama a letter warning him to stay out of Britain’s business. “Regardless of the outcome of the referendum,” the letter reads, “citizens of the United Kingdom should know that we will continue to regard our relations with the United Kingdom as a central factor in the foreign, security, and trading policies of the United States.”

Eyes across multiple continents will be on Britain Thursday, as only time will now tell whether the world is about to witness a national changing of the guard.