How was George Romney eligible to run for the presidency?

[Jerseyrules]

In the immigration act of 1792, it was expressly stated that under the Constitution, America had citizenship jus sanguine.  But, when the Democratic-Republicans repealed this act after they took over Congress in the 1800's, (not for this reason), it was ambiguous on whether this was still the case.

[Jerseyrules]

I think his parents were American citizens.  That's partially why John McCain could run for President despite being born in Panama.

And because Panama was a U.S. territory at the time, and I think there may be an exception if your parents are in the military and you are born overseas