supporter of one's country" is attested from c.1600, but became an ironic term of ridicule or abuse from mid-18c. in England, so that Johnson, who at first defined it as "one whose ruling passion is the love of his country," in his fourth edition added, "It is sometimes used for a factious disturber of the government."
"The name of patriot had become [c.1744] a by-word of derision. Horace Walpole scarcely exaggerated when he said that ... the most popular declaration which a candidate could make on the hustings was that he had never been and never would be a patriot." [Macaulay, "Horace Walpole," 1833]
Somewhat revived in reference to resistance movements in overrun countries in WWII, it has usually had a positive sense in Amer.Eng., where the phony and rascally variety has been consigned to the word patrioteer (1928). Oriana Fallaci ["The Rage and the Pride," 2002] marvels that Americans, so fond of
patriotic, patriot, and
patriotism, lack the root noun and are content to express the idea of patria by cumbersome compounds such as homeland. (Joyce, Shaw, and H.G. Wells all used patria as an English word early 20c., but it failed to stick.)