sentences:  In fact, for many years after the doctrine took effect, Britain, through the Royal Navy, was the sole nation enforcing it, the U.S. lacking sufficient naval capability.The U.S. resisted a joint statement because of the recent memory of the War of 1812, however, the immediate provocation was the Russian Ukase of 1821 asserting rights to the Pacific Northwest and forbidding non-Russian ships from approaching the coast.Despite America's beginnings as an isolationist country, the foundation of the Monroe Doctrine was already being laid even during George Washington's presidency.