A comparable time-span would be Obama invoking Ronald Reagan's first Inaugural of 1981.
In George Washington's precedent-setting first Inaugural he reminded his 'fellow citizens' that he had served as Commander-in-Chief during the Revolutionary War on an expenses-only basis and so proposed to serve as first President without pay.
The closing sentence of Lincoln's second Inaugural has been repeated countless times when, as now, Americans try to look beyond the burdens and sacrifices of war: 'With malice toward none, with charity for all, with firmness in the right as God gives us to see the right, let us strive on to finish the work we are in, to bind up the nation's wounds, [.
Whereas fifteen of the first nineteen inaugurals mention this theme, only nine of the last thirty-three mention it (for a total of 46 percent).
The more important factor is that certain features of American politics seem so permanent and pervasive that new presidents do not even need to think about addressing them in their inaugurals.
This article critiques a prior study paralleling the first inaugurals of Thomas Jefferson and Ronald Reagan.
For earlier content analyses of presidential inaugurals, see John McDiarmid, "Presidential Inaugural Addresses--A Study in Verbal Symbols," Public Opinion Quarterly 1, no.
Second inaugurals form another variant within the inaugural tradition.