The Trump express rolls through the Acela corridor [UPDATED THROUGHOUT THE EVENING]

Today, five primaries were held, all in the so-called Acela corridor. The contests are in Connecticut, Rhode Island, Pennsylvania, Delaware, and Maryland.

Donald Trump is expected to win all five primaries, and has already been declared the winner by Politico in Connecticut, Pennsylvania, and Maryland. In Maryland, this declaration apparently is based on exit polls. As I understand it, the actual vote won’t be counted until 9:00 Eastern Time because the polls were kept open in parts of Baltimore at the request of Donna Edwards, the African-American running in the Democrats’ Senate primary.

In Connecticut, Trump is replicating his impressive New York win of a week ago. With a little less than 10 percent of the precincts in, Trump is at 58.5 percent, more than double John Kasich’s tally and nearly five times Ted Cruz’s (12.6 percent).

The early returns from Rhode Island are even a little better for Trump. He’s at 62 percent.

The Trump express is rolling tonight. The next stop is Indiana. I hope it will slow down there considerably. But if there’s such a thing as momentum in this primary season, Trump has it big time.

UPDATE: Trump has now been declared the winner in all five states. That’s no surprise. But his margins look impressive.

How impressive? Here’s Nate Silver:

[T]he margins are large enough that he could sweep nearly every delegate, except in Rhode Island where allocations are highly proportional.

Suppose that Trump finishes with 100 of 109 delegates tonight, for instance, not counting any uncommitted delegates in Pennsylvania. That would put him on pace for 1,209 delegates, based on the state-by-state projections that our expert panel issued last month, close enough that he could probably get over the top to 1,237 with uncommitted delegates from Pennsylvania or elsewhere.

True, that panel had him winning Indiana, which is a long way from assured. But the point is that Trump has made up the ground he lost in states like Wisconsin and Colorado and put himself in the strongest position he’s been in since March 15.

MEANWHILE ON THE DEM SIDE: The race between Hillary Clinton and Bernie Sanders is over, but their battle in various primaries continues to fascinate me. Tonight, Clinton has been declared the winner in Delaware and Maryland, and it looks like she will win in Pennsylvania. Sanders is running significantly ahead in Rhode Island.

The suspense is in Connecticut, where Sanders leads by around 2 percentage points with approximately one quarter of the vote counted.

CRUZ IS REALLY SCUFFLING: Ted Cruz is having a bad night. In Pennsylvania, he’s in second place, but with only 20.2 percent, as things stand now. Everywhere else, he’s in third place, and in Connecticut and Rhode Island, he’s barely above 10 percent.

The 10 percent mark is significant in Rhode Island because that’s the threshold for winning delegates there.

It’s pretty shocking to see the GOP candidate who’s in second place nationally doing so poorly in any region of the country, now that we’re down to only three candidates.

Too bad the GOP can’t replicate the Whig strategy of 1836, in which four candidates with regional appeal run against Democrat Martin Van Buren. The four were William Henry Harrison of Ohio, Daniel Webster of Massachusetts, Hugh Lawson White of Tennessee, and Willie Person Mangum of North Carolina.

Collectively, they represented the northwest, the northeast, the southwest, and the southeast (as the U.S. was configured at the time).

All four Whig candidates won electoral votes, but not enough to stop Van Buren. He received 51 percent of the popular vote and 170 electoral votes — 22 more than required to be elected president.

TRUMP CARRIES MY DISTRICT: John Kasich had reason to believe he would do pretty well in my congressional district (Maryland’s 8th). For years it was represented (albeit in a somewhat different configuration) by a liberal Republican, Connie Morella. In many ways, Connie could be considered the anti-Trump.

However, Trump has carried the district easily. Last I heard, he led Kasich 44-30. In Montgomery County, the most liberal portion of the district (where I live), the two were in a virtual tie.

Today at my polling place, there was a Trump supporter who was supposed to be greeting voters. The man stood out because he was wearing a suit.

When I entered, he was talking on his cell phone. When I left he was talking to an African-American couple (the only African-American voters I saw). The woman concluded by telling the Trump guy that he’s supporting “a very interesting candidate.”

We tend to be polite in Montgomery County.

DEM UPDATE: Clinton has pulled ahead of Sanders in Connecticut. She leads by a little more than 1,000 votes (about half a percentage point) with two-thirds of the vote counted.

ON THE DELEGATE FRONT: According to Aaron Bycoffe of FiveThirtyEight, it looks like the anti-Trump forces have gained only 7 delegates so far tonight — 5 for Kasich and 2 for Cruz. All in Rhode Island.

Trump is thought to have won 111 delegates so far.

The panel assembled by FiveThirtyEight a little more than a month ago projected that the anti-Trump forces would deny the tycoon 29 delegates and that Trump would capture 118.

Today, Henry Olsen predicted that Trump would pick up 120 delegates, compared to 11 for Cruz and 6 for Kasich. The “uncommitted” total would be 35, Olsen thought.

Trump seems to be outperforming even this scenario.

CLINTON WINS CONNECTICUT: Her lead is up to 6,500 votes with 80 percent counted. Given where the remaining votes are coming from, this lead is good enough for her to be declared the winner.

She goes 4 for 5 tonight.

THAT’S A WRAP, SORT OF: I think almost everything’s been decided that can be decided tonight. The remaining suspense relates to what Pennsylvania’s 54 uncommitted delegates will do down the road. John McCormack discusses this matter.

I think I agree with McCormack that, given Trump’s impressive showing in Pennsylvania, the billionaire will do rather well when it comes to the uncommitted delegates.

Next week, the Cruz campaign will need to demonstrate that it’s still competitive by performing reasonably well in Indiana. He trails there according to the polls, but not by that much.

The real problem seems to be California. There, Trump leads by double digits, and there he could very possibly get close enough to the magic 1,237 number to all but lock up the nomination.

Cruz needs to alter the dynamic of the race, it seems to me — not radically, but discernibly. Apparently, there will be no more debates through which to accomplish this; nor is his non-aggression pact with Kasich likely to do the trick.

I imagine that Team Cruz is thinking seriously about selecting a vice presidential candidate in advance of the California primary.

On that note, I’ll end this post.