Are you familiar with Burma (If not, see here.)?  For example, why do I call it Burma instead of Myanmar?

conventional long form: Union of Burma
conventional short form: Burma
local long form: Pyidaungzu Myanma Naingngandaw (translated by the US Government as Union of Myanma and by the Burmese as Union of Myanmar)
local short form: Myanma Naingngandaw
former: Socialist Republic of the Union of Burma
note: since 1989 the military authorities in Burma have promoted the name Myanmar as a conventional name for their state; this decision was not approved by any sitting legislature in Burma, and the US Government did not adopt the name, which is a derivative of the Burmese short-form name Myanma Naingngandaw (from here)

Here is what the Department of State tells travelers.

Here is what our embassy in Burma has to say.

And if you are really curious what the Department of State has to say about the people of a weak nation ruled by gangsters, see here.