Gordon Tullock used to taunt anarchists by asserting that if the USA abolished its government, people would not have to worry about the Russians taking over the country because “the Mexicans would get here first.”
This little story actually incorporates a common objection to anarchy—namely, the idea that because, if a country abolished its government, other countries would not necessarily follow suit, the governments of those other countries would be free to, and would, simply take over the country that, lacking a government, also lacked an effective means of defending itself against takeover by a foreign power.
This thinking presumes at least two critical ideas: first, that defense of a population requires a government that rules that population; and, second, that if a government has the power to take over another country, it will do so.