Helaman 1

Mormon writes that during the days of Helaman -

"...it came to pass that because of so much contention and so much difficulty in the government, that they had not kept sufficient guards in the land of Zarahemla; for they had supposed that the Lamanites durst not come into the heart of their lands to attack that great city Zarahemla.
19 But it came to pass that Coriantumr did march forth at the head of his numerous host, and came upon the inhabitants of the city, and their march was with such exceedingly great speed that there was no time for the Nephites to gather together their armies.
20 Therefore Coriantumr did cut down the watch by the entrance of the city, and did march forth with his whole army into the city, and they did slay every one who did oppose them, insomuch that they did take possession of the whole city."  (Book of Mormon | Helaman 1:18 - 20)

From both a temporal and spiritual point of view, this could easily happen to us and our so called "capitals" when so much difficulty and contention is taking place in government and society.