You might have read this headline a week ago, "Bruising Primary Has Put Romney in 'Historically Weak' Position", and then this one, "By Historic Standards, Obama is in Trouble", by the same author. So, one of these rules has to be broken … right?

Political pundits and politicians alike like to argue that "this year will be different than any other year". Indeed, here are a few more "rules" that could be broken in 2012.

1. No incumbent party has won the presidency with real disposable personal income growth this weak over a presidential term since 1952.

2. No incumbent president since FDR whose party took over the White House only four years earlier has lost the presidency with gross domestic product (GDP) projected to be as strong as 2012 in the second quarter of the election year.

3. No incumbent president has won re-election with an unemployment rate of greater than 7.2% since FDR. (The unemployment rate is falling, but it's not going to be down to 7.2% by November.)

4. No incumbent president has lost re-election with an approval rating of at least 49% in the Gallup poll. But in a match-up with Mitt Romney, Obama is currently running 3 points behind where his approval rating suggests he should be.

5. No incumbent has won re-election with an approval rating of 48% or below. Obama's approval in the Real Clear Politics average is 47%, but he actually leads by 1.3 percentage points in the Real Clear Politics Obama v Romney average.

6. No presidential candidate since James Polk (in the mid 19th century) has won the presidency without winning his home state or the state he represented in political office. Romney won't win Massachusetts.

At least one of these rules, and likely more, are going to be broken in 2012. The conventional wisdom will be turned on its head: 2012 will indeed be a "unique year". Believers of this idea can also point to the primary season for the uniqueness that is 2012.

Here are three of them that have since gone the way of the Linotype.

1. No Republican candidate had ever won the South Carolina Republican primary without winning either Iowa or New Hampshire – until Newt Gingrich.

2. No Republican had ever won the nomination without winning South Carolina – until Mitt Romney.

3. No non-Protestant candidate had ever won the Republican nomination – until Mitt Romney.

Well, folks, I guess that settles this argument. 2012 will be the baddest, raddest election ever. 2012 doesn't care about the rules. It does what it wants, when it wants.

But here's the thing … every election cycle breaks rules.

Before 2010: no party had ever taken control of the House of Representatives in a general election without also taking control of the Senate since senators were popularly elected.

Before 2008: no Democrat had ever won the presidency without winning Missouri.

Before 2006: no woman had ever been elected speaker of the House of Representatives.

The list goes on and on. I could list more rules broken in each year and go back many years more. Some of these rules are broken because political circumstances have changed.

Romney's not going to win Massachusetts because no Republican wins Massachusetts unless it's a blowout. Even the much-beloved Governor William Weld couldn't win federal office when he ran for Senate in 1996.

The state of Missouri used to be a swing state, but it really hasn't been in the past 15 years. Missouri voted more heavily for George W Bush than did the nation, but because he won the presidency, the rule wasn't broken.

The country as a whole has also become more tolerant on race, religion and equality of the sexes in the past 40 years. That's why a Mormon could win the Republican nomination, why a black man could win the presidency, and why a woman could win the speakership. Given the evolution of public opinion, it was only a matter of time.

Some rules are incomplete and/or don't take into account all necessary confounding variables. All econometric models have margins of error of at least 3.5-4% for a given candidate. Real disposable income projected Gore to win handily in 2000; and doesn't do anywhere as well predicting the vote pre-1952. The GDP model also had problems in 2000 and may be more a circumstance of luck than true explanatory power. And perhaps we should be looking at the change in employment, not the absolute unemployment percentage.

Approval ratings are great at predicting winners, but they are inexact. The perceived ideology of an opponent may not play the biggest role in determining the winner, but it does play some role. Also, these historic approval polls are of adults generally, not actual voters – who tend to be somewhat more Republican.

When voters blame the ruling party enough to throw them out of one house of Congress, then they probably blame them enough to throw them out of both houses. We have had only eight elections where the House has flipped since senators were popularly elected, and the rule doesn't take into account the size of the ruling party's majority or the quality of Senate candidates.

Other rules don't hold because they are simply bad rules that don't have large enough sample sizes. For example …

Mitt Romney's favorables are weak at this point if you only look at data since 1996, but less so when you expand the sample to 1992. Bill Clinton's 1992 net-favorable (favorable-unfavorable) of -12% matched Romney's. I'm sure a favorability poll of Harry Truman, if it existed, would find him in a similar position.

Only two incumbent presidents have lost in the past 70 years, so there really aren't any historical examples. Truman actually trailed by 11 points in April of 1948. Bob Erikson and Chris Wlezien, gods of campaign research, determined that polls at this point in election cycle explain less than 50% of eventual results.

Finally, there had only been six competitive Republican South Carolina primaries prior to 2012. Momentum is built by winning a bunch of primaries, not just South Carolina. Voters there chose a favorite southern son and not someone who had momentum or was able to win outside the Deep South.

Rules are rules in politics … until they aren't rules anymore. Fortunately, as these examples demonstrate, most rules shouldn't be.