If Abraham Lincoln released his October 1863 Thanksgiving proclamation today, it would be panned by all sides. In the statement that is considered the beginning of the unbroken annual tradition of presidential Thanksgiving proclamations, Lincoln said that God had dealt "with us in anger for our sins." He recommended "humble penitence for our national perverseness and disobedience."
The words "sin" and "perverse" would set off the left as overly judgmental and embarrassingly archaic. The right would bristle at national self-criticism from the country's commander in chief (at a time of war, no less). Lincoln had good reason to speak of perversity, of course. He was knee-deep in blood in a Civil War precipitated by half the country leaving the Union so it could protect slavery. But his proclamation was firmly within the American tradition.
The founding generation of presidents struck similar notes. In 1789, George Washington urged that we "unite in most humbly offering our prayers and supplications to the great Lord and Ruler of Nations and beseech him to pardon our national and other transgressions." John Adams in 1798 recommended that religious congregations "acknowledge before God the manifold sins and transgressions with which we are justly chargeable as individuals and as a nation."