What did the Northern states do about slave trade?

By 1804, all of the Northern states had abolished slavery or set measures in place to gradually abolish it, although there were still hundreds of ex-slaves working without pay as indentured servants in Northern states as late as 1840.

Explanation:

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-an amendment is proposed.

-two-thirds of congress must approve.

-thee-quarters of states must approve.

-the proposed amendment becomes law.

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