In 1991, President George H. W. Bush opposed the breakup of the Soviet Union, warning Ukrainians in what became known as the “Chicken Kiev” speech that “freedom is not the same as independence” and “Americans will not support those who seek independence in order to replace a far-off tyranny with a local despotism.” That same year, after Croatia held an independence referendum, the State Department made clear that the United States was committed to the “territorial integrity of Yugoslavia within its present borders” — a stance that did little to prevent the country’s bloody disintegration.

During the first war in Chechnya in 1996, President Bill Clinton dubiously compared President Boris Yeltsin of Russia with Abraham Lincoln, who he said gave his life for the proposition “that no state had a right to withdraw from our union.” Before Scotland’s referendum on independence in 2014, President Barack Obama urged Scottish voters preserve a “strong, robust and united” Britain. The Trump administration, despite flirting with the idea of dropping the longstanding “one China” policy recognizing Beijing’s sovereignty over Taiwan, seems to have settled into a similar embrace of the cartographical status quo.

There have been deviations, notably America’s support for the independence of Kosovo and South Sudan, but these have come to be seen as cautionary tales. Russia used Kosovo as a precedent in recognizing breakaway regions of Georgia, and accused the United States of hypocrisy for not following suit. South Sudan, which has collapsed into civil war and ethnic cleansing, hasn’t exactly bolstered the arguments of independence movements elsewhere.

America’s aversion to border changes conforms with the policies of the world’s major multilateral institutions. Starting in the 1960s, the United Nations backed the independence of former European colonies, but once they were independent, opposed “any attempt aimed at the partial or total disruption of the national unity and the territorial integrity of a country.” This principle was adopted even though many of the new countries had borders drawn by the colonists. Even the African Union, an organization founded on the rejection of colonialism, is dedicated to preservation of one of colonialism’s principal legacies, including language in its charter affirming its members’ “respect of borders existing on achievement of independence.”

At the United Nations’ founding, it had 51 member states. Today there are 193. But the creation of new countries has slowed. In the 21st century, only three new countries have joined the U.N.: East Timor, Montenegro and South Sudan. (Switzerland finally joined in 2002, but it’s hardly a new country.) A few other places, including Kosovo, Abkhazia, South Ossetia and Somaliland, are de facto autonomous but are not universally recognized.