Why should historians use more than one source of information?

two pieces of information are simply always better than one.
one document can give us more than enough information.
a second source might be faulty.
two sources of historical information can give more information than just one.

to oppose fdr’s new deal

explanation:

the american liberty league. the american liberty league was a nonpartisan organization formed in 1934 in opposition to the new deal. the organization's stated goal was “to defend the constitution and defend the rights and liberties guaranteed by that constitution.”