Long before Lincoln's War the states of New York, New Jersey, New Hampshire, Connecticut, Massachusetts, Pennsylvania, Rhode Island, Delaware, and Maryland voted to include slavery into the U.S. constitution. These states voted for slavery along with the states of Virginia, North and South Carolina and Georgia.
And prior to the war not one Congressman or Senator from the northern states - to my knowledge - ever introduced a constitutional amendment to end slavery. Not even Congressman Lincoln.
But there was, of course, a very good reason such an amendment was not introduced: it was not in the economic or political best self-interest of the northern states.
The very good reason that such an amendment was not introduced was because there wasn’t a snow ball’s chance in hell of it ever being passed. The slave states could block any such attempt. Add to this fact that a gag rule about discussing slavery had been enforced in congress since the 1830s so you couldn’t even talk about such an amendment.
Of course not. They knew the political math and understood how devoted the slave states were to their "peculiar institution"
Lincoln did introduce a bill to abolish slavery in the District of Columbia. It went nowhere. Given that failure, why would he attempt the impossible? It could only inflame Southerners without producing any results.
And the price of abolishing the sale of slaves in the District was accepting the Fugitive Slave Law and the rest of the Compromise of 1846.
P.S. When Arlington and Alexandria returned to Virginia in 1846, schools for African-Americans were closed down, because they were illegal in Virginia -- something I just found out researching this.
Something else I just learned: at the beginning of the war, Lincoln wanted the Virginia side restored to the District but the Senate disagreed.