I don't think the question of alien presence in pre-Columbian America continues. Frankly, it has been convincingly and overwhelmingly refuted, basically for lack of any tangible evidence. Fanciful interpretation of a Mayan carving does not qualify..

A lot of these theories start with a fairly racist premise - these folks were so primitive that the only way they could have done what they did was with outside assistance. On the contrary, you can demonstrate a long record (thousands of years) leading to their achievements. At the time they were ravaged by introduced diseases, neither they nor anyone else had an inkling of the germ theory of disease.