Why were Vermont and Massachusetts hardcore Whig states?

[The Arizonan]

Before the Republican Party even existed, Vermont and Massachusetts were hardcore Whig states that have never voted Democrat until the Twentieth Century. Why the trend?

[TDAS04]

Whigs were generally (but far from exclusively) the more Northern-oriented, more antislavery party.  

I'm not entirely sure though.  I have been puzzled by the sharp partisan divides within New England during the Second Party System.  Why were New Hampshire and Maine such hardcore (Jacksonian) Democratic states?

Vermont and Massachusetts seemed to have been the most staunchly abolitionist states.  Even though there were antislavery Democrats in the North--and Whigs in the South were proslavery--Democrats tended to be the party associated with the Slave Power.  Few of the staunchest abolitionists were Democrats, while the most horribly racist defenders of slavery tended to belong the the party of Jackson.  That might have had something to do with why Vermont and Massachusetts were such Whig strongholds, but I'm not certain.