Amid a slew of new swing state polling released today -- six media-sponsored polls in five battleground states (!) -- it's important to remember a very simple electoral fact: Ohio matters more than the other swing states.

This is not simple conjecture. History has shown that no Republican has ever been elected to the White House without Ohio. Without Ohio's 20 electoral votes in 2004, President George W. Bush falls short for a second term. Without Ohio in 2000, he's never elected president in the first place.

But it's not just history. Math -- electoral math to be specific -- makes very clear that Ohio is as close as a must-have for Mitt Romney as exists on the map.

Here's our latest electoral map:

The Fix map has Ohio -- and its 18 electoral votes (the state lost two congressional districts in the decennial reapportionment) -- leaning toward Obama.  The latest poll from NBC/Wall Street Journal/Marist, which shows Obama with a 51 percent to 45 percent edge, confirms that while Ohio has tightened somewhat the President retains a statistically significant edge in the Buckeye State. (The Real Clear Politics poll average in Ohio puts Obama ahead by 1.6 points.)

With Ohio in the fold, President Obama is within 15 electoral votes of the 270 he needs for victory while Romney is 64 electoral votes away -- even if you give him the swing(ish) state of North Carolina, which we currently rate as leaning toward him.

Give Romney wins in the toss up states of Virginia (13 electoral votes), Florida (29), Colorado (9) and Nevada (6) and he still only gets to 263 electoral votes.  Add in Romney victories in Iowa (6) and New Hampshire (4) -- a sweep of every toss up state except Wisconsin -- and Romney wins with 271 electoral votes, the narrowest of margins possible. (Also, not for nothing, 271 electoral votes is what George W. Bush won with in 2000.)

If Romney can turn Ohio back his way, his electoral path widens somewhat.  Take Ohio from Obama and give it to Romney and the president has 237 electoral votes to 224 for Romney, a much closer starting margin.

To win under that scenario, Romney would only need 46 electoral votes more, which he could grab by winning Florida (29), Virginia (13) and Nevada (6) or New Hampshire (4) -- an entirely plausible outcome.

Simply put: With Ohio in his column, Romney has a very credible case to make that he can get to 270 electoral votes. Without it, the case becomes not impossible to make but damn close to implausible. (He could run the table of swing states -- or come close to it -- but that's not the most likely or even an likely outcome at the moment.)

The Romney team -- and Republican more generally -- are well aware of that fact. It's why Romney -- along with super surrogate New Jersey Gov. Chris Christie -- spent the last two days stumping in Ohio. Obama gets Ohio's importance too; he was in the state Tuesday.

As Ohio goes, so goes the presidential race. Again.