Mitt Romney is the least popular presidential nominee in three decades. So what?

Former Massachusetts governor Mitt Romney made history on Monday — but not in a good way.

New polling from the Washington Post and ABC News showed that Romney is the least popular presidential nominee since at least 1984, according to Post-ABC data. (His favorable rating among registered voters is 40 percent while his unfavorable rating is 48 percent.)

In fact, it’s not really that close. Just check out this chart we put together detailing the favorable and unfavorable ratings from Post-ABC polling for the two parties’ nominees dating back to that race.

As you can see, Romney is the first nominee to emerge from the primary process with a significantly higher unfavorable rating than his favorable score, according to Post-ABC polling. (Romney’s fav/unfav numbers have been surprisingly consistent — and bad — for months. Back in September 2011, Post-ABC polling had him at 33 favorable/31 unfavorable and he’s gone downhill since then.)

Those numbers were immediately cast as a sign of doom and gloom for Romney’s chances this fall. But there’s reason to think they might matter less than you think.

First of all, eliminate comparisons to open seat races like 2008, 2000 and 1988. Races without an incumbent have few parallels to the coming race between President Obama and Romney.

That leaves us with four challenger races — 1984, 1992, 1996 and 2004 — that provide a more direct and apt comparison.

In three of those four races, the challenger — at this time (or close to it) — had very strong favorable ratings. Walter Mondale’s favorable ratings was 17 points higher than his unfavorable ratings in 1984 while Bob Dole had a 13 point favorable to unfavorable margin in 1988. John Kerry’s favorable rating was a whopping 28 points higher than his unfavorable score.

What aside from high favorable ratings do Mondale, Dole and Kerry all share? They all lost.

The one challenger who carried a far more middling — 37 percent favorable/37 percent unfavorable rating — was named Bill Clinton. And we know how that one turned out.

What can we learn from those data points? Two things.

1. The outcome of presidential races featuring an incumbent are heavily dependent on how the incumbent fares. A political consultant once told us that in any race featuring an incumbent, 95 percent of the challenge was convincing people to fire the incumbent and 5 percent was getting people to hire the challenger.

In the case of Dole and Mondale, certainly, the incumbents they were challenging (Clinton and Reagan, respectively) strengthened as the election neared. George H.W. Bush, on the other hand, got weaker during the 1992 campaign as his job approval numbers nosedived, handing Clinton a golden opportunity to win. (At this point in 1992, Bush’s favorable rating was 13 points higher than his unfavorable rating.)

2. Campaigns matter. Political scientists would have you believe that the data is determinative. But the data is subject to how each side conducts their respective campaign.

Look back at 2004. At this point in that race, George W. Bush had a 47 percent favorable/46 percent unfavorable score — well below the 54 percent/26 percent rating for Kerry. At that moment, writing that Kerry was a favorite to win wouldn’t have seem far fetched.

But, as the campaign wore on, Bush’s campaign did a number on Kerry. By September 2004, Kerry’s favorable rating stood at 37 percent while his unfavorable rating had soared to 42 percent among registered voters. Bush, on the other hand, had a 52 percent favorable/38 percent unfavorable score at that time.

Make no mistake: Romney would rather not have his name written in the history books for carrying the lowest favorable ratings of any presumptive presidential nominee in modern history. And his campaign clearly has its work cut out for it as they try to re-introduce a more positive/likeable Romney to the general electorate.

But, Obama’s favorable rating — it is currently 11 points higher than his unfavorable score among registered voters — may actually be more predictive as it relates to whether he will win a second term. And, remember that the election isn’t for another 203 days. Lots can and will happen between now and then.