Slaves were private property. If Congress wanted to abolish slavery before the 13th amendment, it would have to have compensated the owners under the 5th amendment. The Dred Scott decision even limited the states’ powers on slavery when it ruled that slaves did not become free when on ‘free soil’.
Before Lincoln’s Emancipation Proclamation (which only applied to areas NOT under US control) Union generals were ordered to return runaway slaves to their owners (but many did resist).
As far as the House possibly passing an antislavery bill, the House was operating under ‘the Gag Rule’ which pretty much prohibited any discussion of slavery. John Quincy Adams spent much of his House career railing against the Gag Rule.
> If Congress wanted to abolish slavery before the 13th amendment, it would have to have compensated the owners under the 5th amendment. <
Very good point. And looking back, it would have been wise had they done so. But who in 1787 could have predicted Antietam in 1862?