Allowing terrorists to come here: Not a domestic enemy
Preventing terrorists from coming here: A domestic enemy
Whack-job territory...
Did the Nazis or Imperial Japanese believe they were the "bad guys"? How about the Viet Cong? Or, more currently, ISIS? Until the right recognizes that the left thinks they hold the superior ethical position, and that we represent all that is evil in the world, some people will continue to underestimate just what the left's intentions truly are. (Hint: force citizens to work, pay taxes and support our designated 3rd world replacements so that the deep state can rule over a new, maleable peasant class.)
With that being said, it's quite easy to simply reverse what you wrote:
Allowing terrorists allies to come here: Not a domestic enemy
Preventing terrorists allies from coming here: A domestic enemy
When citizens inhabiting the same country reach this level of philosophical division, the only solution is for one side to lose, to yield the public square. Consider that Franco ruled for 36 years, and that Spain is still fairly conservative until this day.
As Lincoln stated in his 2nd inaugural address: "Both parties deprecated war, but one of them would make war rather than let the nation survive, and the other would accept war rather than let it perish. And the war came."