Before the conventions, I wrote that "If Obama still leads by 1.5 points once the convention dust has settled, it's difficult for me to envisage how Obama will lose." We are now past the conventions and President Obama still leads.

Any individual national poll is confusing, but the aggregate is a fairly clear Obama edge. Nine pollsters have conducted a survey with a median field date at least a week after the Democratic National Convention. President Obama has led in all of their surveys except for Rasmussen's.

The median result is Obama ahead by 4 percentage points. You might note that the Gallup and YouGov results are among registered voters. Even when we shave 2.5 points off of Obama's margin for a "likely voter" adjustment, the median result is still Obama, by 3 percentage points.

For those who don't like doing the math, a 3-point lead is actually larger than the 1.5-point lead Obama had going into the conventions. The fact that I'm looking only at data one week (or later, for the RNC) after the conventions suggests to me that Obama didn't receive merely a momentary bump but may have gotten the campaign equivalent of a shot of cortisone that will last the rest of the campaign.

The factors underlying this campaign have also not shifted in Romney's direction, but rather in Obama's. In May, I wrote that "the 2012 race comes down to Obama's approvals v Romney's favorables". Take a look at this chart of Romney's favorability ratings since 1 June.

What you see is steadiness or even a slight dip in favorables since the conventions. The absolute numbers are skewed because of different sample populations (likely voters v registered voters v adults), yet the trend is undeniable. Mitt Romney's main electoral failing has been a lack of favorability, and the conventions did nothing to change this factor.

Meanwhile, President Obama's achilles heel had been his low job approval rating. A chart of his approvals since the conventions shows a positive trend.

For the first time in almost a year and a half, Obama's approval is greater than his disapproval in the HuffPollster approval chart. Remember that Obama managed to lead this race when his approval still trailed his disapproval in the HuffPollster chart. As you might expect, his lead has increased, given the rise in his approvals.

The state level data is less clear, but we still can make some keen observations. The baseline electoral college estimate looks like this:

There isn't an analyst in the world who thinks that Barack Obama isn't leading in Ohio right now. It is also fairly clear that Obama's Ohio lead is wider than his national margin. The weighted HuffPollster aggregate, which accounts for house effects and weights state level to regional and national estimates, has Obama running 1.3 points ahead of his national percentage in Ohio. Romney's own political director admits that it's not an "easy state".

If Obama wins Ohio, he's at 255 electoral votes. A win in Florida puts him in the White House for a second term. Let's, for argument's sake, give Romney Florida, even though he trails there. We'll also afford him North Carolina, where he does hold a small advantage. Romney then must take Colorado and Iowa. Both are states where he seems to be running at least equal to his national numbers, if not somewhat ahead. Still, he is probably losing to Obama in both.

Even after giving Romney all these states where he isn't ahead, he is still only at 250 electoral votes. His deficit in Virginia is almost certainly greater than his nationwide hole. A loss in Virginia means he's got to take New Hampshire, Nevada, and Wisconsin. The issue here is that there hasn't been a poll with Romney ahead in Nevada in the last year and a half. Likewise, Wisconsin also seems to be slipping from Romney's grip, with two polls out Wednesday pegging him down by at least 6 points. Only New Hampshire may be trending towards Romney.

The bottom line is that the state level isn't any better than the national picture for Romney. In fact, you can argue that it is considerably worse.

Some Romney supporters might argue that this election is still about the economy and the economy stinks – bad for the incumbent. The truth is that while the economy may not be booming, it is almost certainly good enough to get an incumbent re-elected. Econometric models projecting the election have a 50:50 split. That should give Romney hope for a comeback, but it definitely doesn't guarantee one. John Sides makes a powerful argument that the economy, in fact, favors Obama. That's probably why you've seen Obama catching up to Romney on the question of who can best manage the economy.

But what about a game-changing event? Gaffes like Romney's 47% remarks have shown no ability to move the polls. Debates, as John Sides points out, have historically almost never made a difference. A foreign policy fiasco would almost certainly result in a rally around the leader effect, a la Carter in 1980, before the incumbent gets blamed. There isn't enough time for the "blame" part of the equation to occur before the election.

That's why polls a few weeks after the conventions are usually quite accurate in predicting the result. The economy is usually factored in by voters at this time, and there isn't a campaign event that can alter the playing field fast enough.

Simply put, there hasn't been a single candidate to come back after trailing by 3 points this late in the campaign in the past 60 years.

When I look the current polling data and put it into this historical context, I just don't see a Romney victory. It's not that it can't happen; it's just that 3 points is a good lead in a race that has hasn't shifted easily. Indeed, I wouldn't be surprised if Obama's 3-point lead eventually shrank back to the pre-convention numbers that were so stable for so long. That would fit a historical pattern of tightening before an election. But this race is no toss-up: it now leans pretty hard in Obama's direction.