That is among George Washington's pleas in the first Thanksgiving proclamation (coincidentally, also for Thursday, Nov. 26). We should thank Almighty God for, among several other carefully chosen blessings, "the peaceable and rational manner in which we have been enabled to establish constitutions of government for our safety and happiness, and particularly the national One now lately instituted...." That would include the Federalist Papers. Read President Lincoln's proclamation as well. We should not forget that our now traditional Thanksgiving holiday as the last Thursday in November was finally set during the Civil War. These proclamations constitute core elements of the American civil religion, which reflects and enhances our religious liberty.
Here's President Obama's proclamation. It presents a misleading view of Lincoln's proclamation. Obama claims that "President Abraham Lincoln ... established our annual Thanksgiving Day to help mend a fractured Nation in the midst of civil war." Actually, the mending to be done was through a Union victory--the statesmanlike application of military force to suppress the unconstitutional rebellion. For example, the proclamation recognized the temptations a divided nation offered to ambitious foreign powers. I'm thankful he didn't change the tradition of Presidential Proclamations' echoing of the last words of the Constitution, specifying the date in Declaration of Independence years as well as in the Christian calendar.