Of the following strategies proposed by Senator John J. Crittenden in his 1860 Crittenden Compromise, which one BEST explains why Abraham Lincoln and other Northerners opposed it?
A. amend the Constitution to motivate southern states to rejoin the Union
B. re-establish the Missouri Compromise Line
C. end federal restrictions on slave trade
D. strengthen fugitive slave law
E. re-open slave trade in Washington, D. C.