Worst slap in the face of the past week - Trump telling Kasich that the latter was "stealing" the former's delegates. So much for a Trump-Kasich ticket (unless he does another of his now-famous "I never said that" flip-flops). Kasich is now apparently running on the "they will all come to their senses and choose me" ticket. You see this happen with disfavored sports figures; they keep going on assuming the fans will stop booing them someday. Usually they just become trade material and I don't see Kasich having even that kind of future. He got completely shut out in Wisconsin, but see below.
Sanders pulled another win out. He's going to say "momentum" until his lips fall off but he still needs to win by remarkably large majorities in the upcoming trifecta and I don't see how that happens. More below.
Cruz handed Trump an actual defeat, based on pretty much the perfect storm. Wisconsin had strong popular locals endorsing him, and it has a fired-up conservative activist base that all got on the #stopTrump bandwagon. Yes, Cruz overcame a poll deficit to win, and that's good. Yes, Trump is not building the kind of advantage he would want to lock in a first-ballot nomination, and that's also good. But I don't think it's going to tip the scales significantly.
Upcoming we get to see what something like 10% of the voting electorate think, as New York, Pennsylvania, and New Jersey come into play. The scenario breaks down in various ways, but all of them seem to favor the front-runners.
On the Dem side, New York is home turf to both candidates. Vermont's adjacency makes Sanders known upstate and that part of the state is home to a number of his standard supporters. What it lacks is the vast (white) progressive coalition that gave him Wisconsin. Clinton was the Senator from New York and knows how to campaign across the state. She also draws strong support from the more urban areas of the state, where machine Democrats and strong womens' organizations will back her. Currently she has a double-digit lead in the state polls; I expect Sanders to narrow that somewhat but not overcome it.
Neither Cruz nor Kasich appears to have much of a foothold in New York (yet). Trump is a New York city-ite and yet he plays well to the upstate voters who normally don't go in much for city billionaires. Go figure. The state doesn't have a strong evangelical base that could organize around Cruz. Kasich might pick up some key endorsements that could boost his chances except for the fact that the Republican machine seems to want Cruz to #stopTrump, which is not going to happen here.
PA is a different story - the state has been characterized as Philly on one side, Pittsburgh on the other, and the Bible Belt in between. I haven't seen actual poll numbers but I could see Cruz winning this one if he's able to bring out his base and the Trump support stays tepid. I don't think Cruz has an easy path to victory in PA but I think he has a plausible one. Kasich is the wildcard here. Contrary to Trump's bleating, it's entirely possible that Kasich would take away Cruz voters, particularly in the west of the state. There are a group of very (socially and religious) conservatives there who know Kasich as a neighbor. But they're also in an economically depressed area and those voters have been swinging to Trump. If that quarter of the state gets split up then Trump will win. Cruz will need them in his camp to counter Trump's strength in the cities.
And speaking of the cities, I think they're going to give Clinton her margin of victory in the state. I expect this one to be very close, but both big cities (and some of the smaller PA cities) have politically active minority communities and they seem to be quite solidly in Clinton's camp. I would not be surprised to see Sanders get within 2-3 points of Clinton or even eke out a small win, but I don't see a path to him getting the numbers he needs to narrow her lead.
Finally, NJ. I can't tell whether having Christie's endorsement is going to help or hurt Trump. Christie is wildly unpopular in much of the state now. But the people who hate Christie were never going to vote for Trump anyway so that's not likely to be a huge factor. Like New York I don't think Jersey has a conservative base for Cruz to latch onto; Kasich could very well come second in NJ. Jersey is very ethnically diverse and somewhat economically diverse. But its economic strengths are largely tied to New York City and Philadelphia, both of which I expect to go to Clinton. So, I think, will go the rest of the state.
The bottom line is that all of these things were true before Wisconsin and they remain true after Wisconsin. What that state's voting proved is that both Cruz and Sanders absolutely should stay in the race. They may not have easy roads ahead but they do have paths and what they do matters.