A reader in the comments:

Consider the ratio of winners' votes to runners'-up votes in the last 25 Presidential elections.

Obama won a clear victory with a ratio of 1.13 over McCain. (63.0 / 55.8 = 1.13)

But by any reasonable historical standard, this election was actually fairly close.

The average over the last 25 elections has been 1.30. For the last 12 its 1.22....

Winner RunnerUp Ratio Contest

2000 0.479 0.484 0.98 Bush - Gore

1960 0.497 0.496 1.00 Kennedy - Nixon

1968 0.434 0.427 1.01 Nixon - Humphrey

1976 0.501 0.48 1.04 Carter - Ford

2004 0.507 0.483 1.04 Bush - Kerry

1916 0.492 0.461 1.06 Wilson - Hughes

1948 0.496 0.451 1.09 Truman - Dewey

2008 0.52 0.46 1.13 Obama - McCain

1992 0.43 0.377 1.14 Clinton - Bush

1944 0.534 0.459 1.16 Roosevelt - Dewey

1988 0.534 0.456 1.17 Bush - Dukakis

1996 0.4924 0.4071 1.20 Clinton - Dole

1940 0.547 0.448 1.22 Roosevelt - Willkie

1980 0.507 0.41 1.23 Reagan - Carter

1952 0.552 0.443 1.24 Eisenhower - Stevenson

1956 0.574 0.42 1.36 Eisenhower - Stevenson

1928 0.582 0.408 1.42 Hoover - Smith

1932 0.574 0.397 1.44 Roosevelt - Hoover

1984 0.588 0.406 1.44 Reagan - Mondale

1912 0.418 0.274 1.52 Wilson - Roosevelt

1964 0.611 0.385 1.58 Johnson - Goldwater

1972 0.607 0.375 1.61 Nixon - McGovern

1936 0.608 0.365 1.66 Roosevelt - Landon

1920 0.603 0.341 1.76 Harding - Cox

1924 0.54 0.288 1.87 Coolidge - Davis

It's only because the last two elections were so close that this one seems remarkable. I don't know that I'd call it "fairly close," but it certain isn't a blowout, landslide, tsunami, etc., by historical standards, but just a mundane victory.