Almost Every Swing State Is A ‘Must Win’ For Trump Now But if the race tightens, that will change.

The impact of the three presidential debates — particularly the first — has borne itself out in the polls in many ways. Hillary Clinton won the first debate decisively, jumped out to a 5 or 6 percentage point lead nationally, according to the FiveThirtyEight polls-only model, and hasn’t dropped below that threshold since. As a result, Donald Trump’s options in the Electoral College have been significantly narrowed; Clinton’s have proliferated.

You can see Trump’s deteriorating map clearly by looking at how our “must win” numbers have shifted. A week before the first debate, both Trump and Clinton had certain “must win” states. That is, according to our polls-only model, there were a number of swing states (as indicated by our tipping-point calculation) where Clinton and Trump won the election in the vast majority of cases where they won that state.

IA OH FL NC NV NH CO MI WI PA VA MN ME NM Clinton’s chances if she wins state 95 95 94 91 87 82 82 80 80 79 75 75 74 70 Clinton’s chances if she loses state 39 33 28 34 32 21 18 9 10 13 12 10 19 20 Trump’s chances if he wins state 61 67 72 66 68 79 82 91 90 87 88 90 81 82 Trump’s chances if he loses state 5 5 6 9 13 18 18 20 20 21 25 25 26 30 Clinton and Trump have different ‘must-win’ states (Sept. 19) All values are percentages. FiveThirtyEight polls-only forecast as of Sept. 19.

Before the first debate, our forecast showed Clinton winning the election more than 90 percent of the time she was able to defeat Trump in Florida and North Carolina, for example. Trump was forecasted to beat Clinton about 90 percent of the time when he won in Pennsylvania and Wisconsin. Put another way, Florida and North Carolina are slightly red-leaning states, so if Trump loses them, he’s most likely losing the election. Pennsylvania and Wisconsin are light blue, so if Clinton is losing there, she’s likely to lose overall.

You’ll further note that Clinton’s percentage chance of winning the election if she won a certain state generally ran close to Trump’s in the aggregate. Across these 14 states, Clinton’s chance of winning the election if she won a given state averaged 83 percent. Trump’s chance of winning the election averaged 79 percent. That was indicative of a relatively tight race, with Clinton having a slight advantage.

Now take a look at these same 14 states as they stand with 11 days to Election Day. Clinton’s chances of winning the election if she wins a given swing state average 92 percent. Trump averages only 60 percent.

CANDIDATE CHANCE OF WINNING ELECTION IF THEY WIN STATE STATE CLINTON TRUMP Virginia 87% 79% Michigan 91 78 Wisconsin 91 77 Minnestoa 90 75 Pennsylvania 90 72 Colorado 90 70 New Mexico 85 65 New Hampshire 90 62 Maine 87 58 Florida 98 49 North Carolina 96 46 Nevada 95 45 Iowa 98 37 Ohio 99 35 Trump has many more ‘must win’ states than Clinton right now All values are percentages. FiveThirtyEight polls-only forecast as of 11 a.m. on Oct. 28

This decline for Trump tells us that there’s no magic bullet for him in terms of the electoral map anymore. Clinton has many more paths to victory. She can afford to lose any of these 14 states and still have somewhere between a 21 percent and 64 percent chance of winning. There’s not a single state now where Trump wins the Electoral College in at least 80 percent of the simulations if he wins that state. Back in September, Trump won at least 90 percent of our simulations if he won anyone of three states: Michigan, Minnesota or Wisconsin.

Trump now has five states, on the other hand, that if he doesn’t win, he loses the election 95 percent of the time or more. Some of these are generally understood to be states more friendly to him, such as Iowa and Ohio. They also include, however, Florida and North Carolina where he is currently trailing in most of the polling. Clinton actually still wins in a majority of our simulations in which she loses one of these.

This difference between what winning either of these states means for Clinton and Trump is something you should keep in mind going forward. Florida and North Carolina are important not because Trump’s winning them means he’s going to win the election. Rather, Florida and North Carolina are important because a Trump victory in either of them indicates that we have a more competitive race nationally. A loss by Trump in either one probably means the polls are right, and Clinton is going to win the election.

But comparing Trump’s and Clinton’s “must-win” numbers from before the first debate and now also illustrates a danger for Clinton. Trump has few paths in the Electoral College because he’s losing nationally by 5 or 6 percentage points, not because there’s anything inherent about the map that favors Clinton. Almost all the swing states are now “must win” for him, but if the race tightens, that will change.