Donald Trump's week of bad polls just got much worse.

Four new NBC News/Marist College polls released Friday show Democratic presidential nominee Hillary Clinton leading her Republican rival by five points in Florida, nine points in North Carolina and double digits in Colorado (14) and Virginia (13). All four states have been battlegrounds in recent presidential elections.

And really, it's those last two numbers that show just how massively difficult Trump's path to the presidency is right now. Because without Colorado and Virginia — and a third state where he trails by double digits, Pennsylvania — he's all but sunk.

National polls have gone up and down, and a few this week even show Trump within striking distance of Clinton. But national polls aren't what matter; the Electoral College does. And the numbers in Colorado, Virginia and Pennsylvania are basically prohibitive for Trump right now.

According to Real Clear Politics, the last four polls in Pennsylvania have shown Trump down by 10 to 11 points. In Colorado, the last three polls show margins of 10 to 14 points. In Virginia, Trump has trailed by double digits in the last two polls and by as much as seven and nine points in other recent polls.

The Clinton campaign and its allied super PAC have even taken the bold, confident step of pausing ads in Colorado and Virginia.

But here's the thing: These aren't just three of a handful of battleground  states. Trump simply can't lose all three to win. And he probably can't even lose two of them.

That's because Democrats have a built-in advantage in the Electoral College. As our own Chris Cillizza wrote, Clinton basically starts with 242 of the 270 electoral votes she needs if she can just hold the 19 states that Democrats have won in each of the last six presidential elections, which includes Pennsylvania. If she wins all those and adds Florida, with its 29 electoral votes, it's game over.

In that scenario, she can even lose Colorado, Virginia and essentially every other regular swing state — along with New Mexico, which isn't competitive this year but which Republicans have won in recent decades — and still win the election.

Now, Trump has actually polled quite competitively in Florida, with most recent polls showing a virtual tie. But even if he wins there, he can't survive losing Colorado, Pennsylvania and Virginia. Losing all three and New Mexico would put Clinton at 269 electoral votes — just one shy of victory.

From there, all Clinton would need to do is win one of the following: Nevada (6 electoral votes), Iowa (6), Ohio (18), New Hampshire (4) or North Carolina (15). Oh, and remember that the new NBC/Marist polls shows Clinton up nine points in North Carolina, and a poll this week showed Clinton up 17 (!) in New Hampshire.

And if you throw in New Hampshire and give Clinton every battleground state in which she currently leads by double digits in the most recent poll, she's already won with 273 electoral votes.

Again, this is assuming Trump wins every state in which he's not currently down double digits. He still loses.

As we move forward in this campaign, the polls in Florida will be really important — and will be treated as such. It's essentially a must-win state for Trump.

But Florida is a moot point if Trump continues to trail by double digits or even close to it in Colorado, Pennsylvania and Virginia.

What Donald Trump is doing on the campaign trail

MANCHESTER, NH - NOVEMBER 7: Republican presidential candidate Donald Trump speaks during a campaign event at SNHU Arena in Manchester, NH on Monday November 07, 2016. (Jabin Botsford/The Washington Post)