Although Donald Trump is essentially tied with Hillary Clinton in the polls, he is still unlikely to win the presidency, thanks to the Blue wall.
Eighteen states and the District of Columbia have voted Democrat in every election since 1992. That's six consecutive elections. Those states collectively represent 242 Electoral College votes, just 28 votes short of the 270 needed to win. This is the Blue wall.
To defeat Hillary Clinton, Mr. Trump must either tear down that wall, or find a way around it. With less than seven weeks to go until D-Day, the evidence suggests the Republican presidential candidate will fail.
Consider: Just to get in the game, Mr. Trump must win everything Mitt Romney won in his losing effort of 2012, including such volatile states as North Carolina (15 Electoral College votes) and Indiana (11). That would give him 206 Electoral College votes.
Then he must win the key swing states of Florida (29) and Ohio (18). That's no easy feat, and he would still be at 253 Electoral College votes, 17 short of what he would need to win. To squeak over the line, Mr. Trump would need to take Colorado (9), Nevada (6) and New Mexico (5). All three states went Democrat in 2008 and 2012, but have voted Republican in previous elections. A single loss in any of these states could doom his chances, unless he took Virginia (13). That southern state was once reliably Republican, but has swung over the Democrats in the past two elections, thanks to the affluent suburban commuters living outside D.C.
The only other path to victory involves cracking the Blue wall – swinging a large and heretofore reliably Democratic state over to the Republicans. Most observers believe Mr. Trump's best chance lies in Pennsylvania, which combines affluent suburbs with industrial wastelands. If Mr. Trump could win Pennsylvania, he would add 20 Electoral College votes to his column, which would make it possible to lose the smaller swing states and still prevail.
So how is Mr. Trump doing in these battleground states? Not badly, but at this point, not well enough.
According to the RealClearPolitics compendium of polls, Ms. Clinton is 6.6 points ahead of Mr. Trump in Pennsylvania. The Blue wall remains intact.
Mr. Trump's problem in Pennsylvania centres on "his weakness among suburban voters, especially women," according to an analysis by Peter Morici, a well known political analyst who teaches at University of Maryland.
"Similarly, his strength with blue collar men is likely not enough to overcome his weakness among more-educated, middle class women in several other battleground states."
In Virginia and Colorado the Clinton camp holds a slimmer lead of between 3 and 4 points. The two campaigns are essentially tied in Florida, Ohio and Nevada. Polls in New Mexico are contradictory.
Surprisingly, Mr. Trump has a healthy four-point-lead in the small state of Iowa (6). But Ms. Clinton is tied with Mr. Trump in North Carolina and is putting up a strong fight in the traditionally Republican state of Arizona (11), where she is less that two points behind.
Mr. Trump's incendiary comments about Latinos and Muslims damage his credibility among suburban middle-class women voters, Prof. Morici believes, as do his threats to tear up the North American Free Trade Agreement and to launch a trade war with China.
"They shop at Walmart, are skeptical about balancing family budgets without inexpensive goods from China, and many recognize the United States can't simply rip up NAFTA without wholly destabilizing Mexico and causing millions more to try to cross our southern border," he wrote.
Bottom line: If an election were held tomorrow, Ms. Clinton would almost certainly post a narrow win in the Electoral College. If Mr. Trump's support has peaked, then he has lost.
Of course, his support might not have peaked. Much could hinge on the unpredictable candidate's performance during the televised debates. There could be unpleasant surprises for the Democrats in October.
But the Blue wall is a great obstacle to Republicans. And while Mr. Trump's incendiary campaign is popular with some, some may not be enough.