The Clinton Campaign Seems To Think Pennsylvania Is In The Bag But it shouldn’t bank on it.

Hillary Clinton has a substantial lead in the polls over Donald Trump, and has vastly more cash on hand. But when it comes to spending that cash, her campaign may be making a strategic miscalculation. The campaign and an allied super PAC have reserved $137 million of ads across eight states — yet they’ve conspicuously left out the state that might be likeliest to tip the 2016 election: Pennsylvania.

Michigan and Wisconsin were absent from the list, as well, but the Keystone State is the most curious Rust Belt omission. In May, we laid out the case for why the Keystone State could be on pace to decide a close national race. Evidently, Democratic ad strategists don’t share that view. Last week, former Obama advisor David Plouffe tweeted that the buy “shows real discipline” because “PA is not a true battleground.” That’s a bit of bravado, considering it was tied for Obama’s fourth-closest win in 2012.

STATE 2012 OBAMA MARGIN ELECTORAL VOTES AD RESERVATIONS 1 Florida +0.9 29 $35.1m – 2 North Carolina -2.0 15 14.3 – 3 Ohio +3.0 18 27.9 – 4 Virginia +3.9 13 11.8 – 5 Colorado +5.4 9 15.6 – 6 Pennsylvania +5.4 20 0.0 7 New Hampshire +5.6 4 8.8 – 8 Iowa +5.8 6 11.3 – 9 Nevada +6.7 6 13.1 – 10 Wisconsin +6.9 10 0.0 2016 Pro-Clinton ad reservations in closest 2012 states Includes ad reservations by Hillary Clinton’s campaign and the Priorities USA 2016 superPAC Source: Kantar Media/CMAG

Many Democrats take Pennsylvania for granted because it hasn’t voted Republican in a presidential election since 1988. But in 2012, its margin for President Obama was just 5.4 percentage points, equal to his margin in Colorado and less than his margins in Iowa, New Hampshire and Nevada — all states included in early pro-Clinton ad reservations this year. Moreover, unlike those four states, Pennsylvania has trended toward Republicans over time, thanks to its older, whiter and more working-class electorate:

It’s true that Obama didn’t do much advertising in the state in 2012, but then again, neither did Republicans or the Romney campaign.

To be fair, pro-Clinton strategists aren’t simply throwing darts at the map. The Clinton campaign employs a phalanx of pollsters and targeting experts, and aides hint that its sophisticated data analytics contradict recent public polls depicting a very tight contest in Pennsylvania. Asked directly about its lack of an ad buy, the Clinton campaign declined comment except to confirm that it has placed field staff in the state.

Their decision not to spend in Pennsylvania may yet be vindicated, and of course, the state won’t matter if Clinton is headed for a national blowout win. But there is ample publicly available data to suggest Pennsylvania could be problematic for Clinton in a close national contest.

Since November of 2008, Democrats’ voter registration edge in the Keystone State has shrunk from 14.2 percent to 11.1 percent — a pattern that more closely resembles the rightward cultural shift of West Virginia than the leftward migration of New Jersey. In fact, in 60 of Pennsylvania’s 67 counties (save for Philadelphia and six other eastern Pennsylvania counties), the party registration trend over that time has favored Republicans.

So far this year, 73,543 Democratic registrants have switched to the GOP. The switchers mostly live in heavily white, working-class counties, and most did so in advance of the April 26 primary, presumably to vote for Trump. Trump took 57 percent statewide, but he took 70 percent in Fayette County (Uniontown) and 77 percent in Luzerne County (Wilkes-Barre) — locales that recorded two of the highest rates of party switching.

It’s likely that many of these “Trump Democrats” were already Romney voters in 2012. But it’s also possible that Trump has room to grow with Pennsylvanians who didn’t click with either Romney or Obama four years ago. According to Census data, just 63 percent of Pennsylvania’s eligible non-Hispanic whites turned out to vote in 2012, compared with an average of 68 percent in the other nine closest states.

It’s understandable that Clinton and her allies want to stay on offense rather than get bogged down playing defense. And of course, Democrats will hold their convention in Philadelphia next month. Clinton’s campaign is undoubtedly monitoring the Keystone State, and the campaign or associated super PACs could quickly negate the premise of this article if they shift their ads from Las Vegas to Pittsburgh next week.

Traditionally, however, this is an important getting-to-know-you phase of the campaign. In 2012, this was the period when Obama created real separation in a lot of swing states by defining Romney before Romney could define himself. It’s surprising that so far, neither Clinton nor her allies are taking more aggressive steps to shore up her Rust Belt standing.

CORRECTION (June 22, 9:30 p.m.): A previous version of this article misstated the year when a Republican presidential candidate last won Pennsylvania. It was 1988, not 1998.