What U.S. presidents seeking re-election fear most is the wrath of a rising misery index. And nothing brings more misery to the world's largest oil consuming economy than high oil prices.
During the 1960s, Arthur Okun, an American economist, created the idea of a "misery index" to measure economic hardship. It was simply the sum of the nation's unemployment rate and its inflation rate, assuming the two to be equal in the costs they impose on society.
The concept was popularized by Jimmy Carter, who used it during his presidential campaign in 1976 against incumbent Gerald Ford, claiming no president who had imposed so much misery on the electorate could ask to be returned to office. At the time, the index was 13.5 per cent.
When you live by the misery index, you die by the misery index.
Mr. Carter's use of the concept may have helped him unseat Mr. Ford but by the time the next election rolled around, the index had risen to an all-time high of almost 22 per cent. While Ronald Reagan didn't campaign against Mr. Carter on the index, he didn't have to. With both inflation and the unemployment soaring, the American electorate was more than aware of their level of economic hardship, and they summarily voted Mr. Carter out of office.
For the past 30 years, the ebb and flow of U.S. presidential elections have followed the broad movements in the nation's misery index. The index plunged during the Reagan years, which went a long way in explaining his enduring popularity and re-election to a second term.
It stopped falling during the term of his successor, George H.W. Bush, and it was the context for Mr. Bush's subsequent defeat to Bill Clinton during the "It's the economy stupid" campaign of 1992. Just as a falling misery index re-elected Mr. Reagan in the 1980s, it re-elected Mr. Clinton in 1996.
That is an impressive track record, but not a surprising one. What it tells you is the economy's performance is ultimately what the U.S. electorate cares the most about when they vote for a president.
And nothing has been more important to the performance of the U.S. economy than the price of oil. Mr. Carter was a victim of the stagflation of the OPEC oil shocks, while Mr. Reagan rode the wave of plunging oil prices when those shocks subsided. Not surprisingly, soaring oil prices after Iraq's invasion of Kuwait was the backdrop for the economic downturn that cost Mr. Bush his presidency to Mr. Clinton.
None of this can be reassuring for President Barack Obama's re-election prospects. The misery index is at about the same level (13 per cent) that cost Mr. Carter his election. And oil prices are once again centre stage when it comes to both explaining a near double digit jobless rate and rising inflation. Brent-based world oil prices have traded in triple digit range since the beginning of the year.
Will high oil prices once again claim a presidency as it has done so many times before?