Juneteenth is the nation’s newest national holiday, commemorating June 19, 1865, when a Union general informed the last enslaved people in Texas that they were free.

There was virtually no articulate opposition to slavery in the North American colonies that rebelled against British rule in the 1770s. But there was an obvious tension between slavery and American assertions of individual rights, encapsulated in Thomas Jefferson’s phrase “all men are created equal.” Revolutionaries were uncomfortably aware of the great English writer and lexicographer Samuel Johnson’s remark, “How is it that we hear the loudest yelps for liberty among the drivers of negroes?”

Americans in northern states responded. In 1781 and 1783, Massachusetts trial and appeals courts ruled that slavery violated the commonwealth’s 1780 constitution, and later in the decade, New Hampshire courts agreed.

These resembled Lord Chief Justice William Mansfield’s 1772 decision in Somerset’s case that slavery did not exist in England.

In 1780, the Pennsylvania legislature, declaring slavery “disgraceful to any people, and more especially to those who have been contending in the great cause of liberty themselves,” passed a law gradually freeing slaves.

Similar laws, granting freedom to slaves aged 25 born after the law’s enactment, were passed in Rhode Island and Connecticut in 1784; in New York at the behest of Gov. John Jay in 1799; and in New Jersey in 1804. In July 1787, the Continental Congress passed the Northwest Ordinance outlawing slavery in the Northwest Territory — the future states of Ohio, Indiana, Illinois, Michigan and Wisconsin.

The historian Alan Taylor, in his books “American Revolutions” and “American Republics,” reminds readers that emancipation was gradual, motivated “more from a distaste for slavery than from empathy for the enslaved.”

It is easy to judge these early antislavery measures as insufficient by 21st-century standards. But they can be defended as the best that practical politicians could do to put the “peculiar institution” on the “path to extinction.”

Tragically, the trend did not extend far southward. Virginia in 1782, Delaware in 1787 and Maryland in 1790 passed manumission laws, regularizing granting freedom to slaves. By 1860, 92% of Black people in Delaware and 40% in Maryland were free.

But Virginia repealed its manumission law in 1806, and in the 1820s, rejected attempts to abolish slavery.

But if Virginia and the Deep South became staunch defenders of slavery, the Northwest Territory’s ban on slavery made it fertile ground for opposition to the extension and perpetuation of slavery.

Efforts to permit slavery in Ohio were defeated by legislator Ephraim Cutler, whose father played a key role in inserting the ban in the Northwest Ordinance, as David McCullough explains in his latest book, “The Pioneers.”

In Illinois, a key role was played by Edward Coles, a young private secretary to President James Madison, who brought his inherited slaves to the prairies, bought them farmland and freed them. As governor of Illinois in the 1820s, Coles defeated the legislature’s attempt to legalize slavery, a story told dramatically in Suzanne Cooper Glasco’s “Confronting Slavery” and in Kurt Leichtle and Bruce Carveth’s “Crusade Against Slavery.”

Edward Coles lived to witness the 13th Amendment and the original Juneteenth. This Juneteenth is a good time to remember him and the many others who strived to put American slavery on the path to extinction and, thankfully, finally succeeded.