Answer:
Fredrick Douglass was a runaway enslaved person who became one of the most outspoken critics of slavery in the United States during his time.
In the first part of the quote; “America is false to the past", Fredrick meant that the United States was misinterpreting the words of the Constitution in using it to justify slavery as the Constitution was in fact against slavery according to him.
In the next part of the quote, Douglass notes that in the present (his present), the U.S. were also wrong in passing laws such as the Fugitive Slave Act that perpetuated slavery and in the last part he believes that should the U.S. continue as it was going, it would be continue to the wrong in future.