It is time for opposition to the Annexation of Texas to cease.... Texas is now ours.... Let their reception into the "family" be frank, kindly, and cheerful (O)ther nations have undertaken ... hostile interference against us, ... h pering our power, limiting our greatness and checking the fulfillment of our manifest destiny to overspread the continent allotted by Providence (God) for the free development of our yearly multiplying millions.

Question

It is time for opposition to the Annexation of Texas to cease.... Texas is now ours.... Let their reception into the "family" be frank, kindly, and cheerful (O)ther nations have undertaken ... hostile interference against us, ... h pering our power, limiting our greatness and checking the fulfillment of our manifest destiny to overspread the continent allotted by Providence (God) for the free development of our yearly multiplying millions.

California will, probably, next fall away from (Mexico).... Imbecile and distracted, Mexico never can exert any real governmental authority over such a country... The Anglo-Saxon foot is already on (California's) borders.... ?
armed with the plough and the rifle, and marking its trail with schools and colleges. courts and representative halls, mills and meeting-houses.... All this (will happen) in the natural flow of events...

What do you suppose O’Sullivan means by “the Anglo-Saxon foot”?

Answer 1

O'Sullivan is referring to the influx of American settlers, primarily of Anglo-Saxon descent, into California. He is suggesting that the American settlers will bring with them their culture, values, and way of life, which will be spread throughout the region as they settle and establish communities.