Scoitland has been invaded by many groups of people and generally fended them all off from the Romans to the Vikings to the English.
however in 1706/7 from when the act of union was passed(in an illegally convened parliament btw ) GREED and corruption was used to sway the vote. the people of the time certainly didn't want the union as the riots all over Scotland from Dumfries,to ayr,Edinburgh,Glasgow,Aberdeen,Dundee.. all over testify.
Scotland was pout in a vulnerable position by naval blockade which ,apart from a shitty choice of trading goods, put paid to the Darrien scheme. Privateers were also commissioned to raid Scottish vessels too, then there was the alien act making it illegal to employ,trade with,house or shelter a Scot in England or even trade with them abroad
Now... while the towns and cities were actually ok for funds the merchants and noblemen were fucked by the failed investment in the Darrien scheme and also by the alien act.
A rather famous writer of the time was employed by the crown to bribe his way through the Scottish parliament and being in desperate need of funds or just being greedy corrupt bastards the vote got through
That was Daniel Defoe who was the paymaster and handler for the agents of the crown
Thus it can be said that the only country to totally defeat Scotland ...were... ourselves due to those corrupt fucks.
As a side note... if you look at the 'Bella Pasta' eatery on teh corner of the royal mile and North Bridge, in the basement of that building where the eateries toilet is now placed.. that's where the act of union was drafted and then completed for presentation to the parliament for the vote.
quite appropriate as it was concocted by shits and pushed through by shits and therefore ,generally,a bit of a shitter! ;)