Modern liberals are worse than the 19th century slaveholders and slavery apologists were. Like their ideological forefathers, abortion defenders deny the humanity of the victim and act as though the only issue is whether people should be free to own or kill the most defenseless among us.
Abortion was widely legal in America in the 18th and early 19th century.
Oh, really?! Define "widely legal." England banned abortion in 1803. By the 1820s, state laws began to ban abortion. That trend accelerated in the 1860s. By 1900 abortion was a felony--yes, a felony--in every state.
But, if you want to appeal to precedent, slavery was "widely legal" in America for decades before the founding of the country until the end of the Civil War.