The past 14 months have had their fair share of historic moments — the killing of Osama bin Laden, the ongoing debt crisis in Europe, the debt ceiling fight, the Republican presidential primary fight and the Supreme Court’s ruling on President Obama’s health care law to name just a handful.

And yet, in spite of the massive news coverage that each of those stories has drawn, none of them seem to have impacted the race between President Obama and former Massachusetts governor Mitt Romney in any meaningful way.

As the Post’s Dan Balz and Jon Cohen write in their story on the most recent Washington Post-ABC News national poll, only twice in the 13 surveys conducted since last April has either candidate had a lead outside the statistical margin of error — both times it was President Obama — and the latest survey shows the two men tied at 47 percent each.

Here’s a chart that shows the remarkable parity present in the numbers over the past 14 months — with Obama typically running in the mid to upper 40s and Romney in the low to mid 40s.

The consistency of those poll numbers — particularly amid well more than $100 million in spending on TV ads alone by the two candidates — is akin to a beach umbrella never wavering amid a series of very strong gusts. The numbers, like the umbrella, are rooted in place.

Partisans — even weak partisans — have already been pushed into their respective camps and there’s very little evidence they plan to move. Of Obama’s 47 percent support in the latest Post-ABC poll, just three percent said they could change their mind on supporting him; just 5 percent of Romney backers said the same.

No external events — no matter how large or how impactful to the country — will sway these people. Their minds are made up.

And so, what the two campaigns are left with is trying to figure out how to reach the six percent (or so) of people who have genuinely not made up their minds about who to support yet. What moves those people? That’s what Obama and Romney will spend the next four months trying to divine.