If you're contending that the tariff issue helped to drive the secession movement, was the subject raised by Sydenham Moore, George S Houston, or anyone else at the Alabama Secession Convention? Was secession about the tariff, or something else?
If that's your contention, reasonable arguments might be made to support it.
http://www.kosmosonline.org/group-post/did-tariffs-really-cause-civil-war-morrill-act-150
http://cwcrossroads.wordpress.com/2011/01/25/tariffs-government-policy-and-secession/
http://www.northcarolinahistory.org/commentary/81/entry