Why is this so complicated?
The issue isn’t when an individual should receive Miranda rights, but who should receive them. American citizens, who are entitled to Constitutional Rights, should receive Miranda warnings. That includes American citizens who are terrorists; See Timothy McVeigh and Faisal Shahzad. The flip side are those who are not American citizens. They should not receive Miranda rights (or a trial in American courts).
This is such a simple issue that one has to wonder why the Administration’s proposed fix is figuring out how to effectively decrease the rights of American citizens by expanding a narrowly-tailored exception to Miranda.