In their petitions to Congress abolitionists frequently called for what?

A political campaign was the final element of the abolitionists' program. In 1835,

the American Anti-Slavery Society bombarded Congress with petitions demanding

the abolition of slavery in the District of Columbia, an end to the interstate slave trade,

and a ban on admission of new slave states. By 1838, petitions with close to 500,000

signatures had arrived in Washington.

Henretta, James A. and David Brody. America: A Concise History, Volume I: To 1877. 4th ed., Boston: Bedford/ St. Martin's, 2010. Chapter 11 page 338