The Cruz and Sanders victories set up both parties for more uncertainty and contention

So where are we now?

Short answer: With less clarity than we had as April began, only days ago. With greater likelihood of at least one contested midsummer convention, a faint prospect only months ago. With new pressures on the frontrunners and new opportunities for the underdogs, newly invigorated but still facing a difficult battle.

Those underdogs swept to victory Tuesday in Wisconsin, stealing the momentum of the two frontrunners, recasting the wild story line of Campaign 2016, adding a dash of uncertainty to the Democratic race and tossing a pinch of chaos into the Republican contest.

With decisive victories in a state populated by new-age conservatives in the Republican Party and old-time liberals in the Democratic Party, Sen. Ted Cruz of Texas and Sen. Bernie Sanders of Vermont defeated the two party frontrunners in contests that may not be game-changers — but that certainly have changed the narrative of the 2016 campaign.

Their twin triumphs raised fresh questions about the electability of Manhattan businessman Donald Trump and former Secretary of State Hillary Rodham Clinton, raised the prospects of the first brokered convention in two-thirds of a century, raised the stakes of this month’s New York and Pennsylvania primaries and raised the bar on campaign fundraising. In a remarkable blaze of small-donor contributions, for example, Mr. Sanders took in $15 million more than Ms. Clinton last month.

As recently as midwinter, the silt loam of Wisconsin seemed fertile territory for both frontrunners, Mr. Trump because the state had recent experience with a rebel-Republican governor and Ms. Clinton because her profile so closely matches that of the Robert La Follette reformers who introduced the word “progressive” into the American political lexicon a century ago.

But in a year when all the assumptions turned out to be written in the past tense, Wisconsin turned out to be an ideal proving ground for insurgents to upend frontrunners — even frontrunners who themselves carefully cultivated their own images as insurgents.

This is only the second time in more than a half-century that Wisconsin, which sometimes ends campaigns but rarely adds new oxygen to them, has played this significant a role in a nominating contest. In 1960, it was the stormy venue for the first important confrontation between Sen. John F. Kennedy of Massachusetts and Sen. Hubert H. Humphrey of neighboring Minnesota. Mr. Kennedy prevailed, fortifying his position as a formidable political force, but as the results were coming in, the two men actually watched the vote tally on chalk boards in the city room of The Milwaukee Journal, where the scene, according to the newspaper’s Rod Van Every, “varied from orderly chaos to disorderly chaos.”

The spectrum from orderly chaos to disorderly chaos now describes perfectly the situation in both parties.

Mr. Sanders now claims substantial momentum — momentum that he almost certainly will claim again Saturday, when Wyoming provides him with the majority of its merely 18 delegates in its caucuses.

But the road from Cheyenne and Laramie, the two largest university cities in the state and thus the power centers for a candidate with enormous youthful support, to the Philadelphia convention is full of obstacles. Mr. Sanders is behind in five of the six following contests, with bright prospects only in Rhode Island, which has only 33 delegates at stake. Together, Wyoming and Rhode Island account for a mere 1.1 percent of the Democratic delegates.

Among the big challenges that loom for the Vermonter: The last two reliable polls put Ms. Clinton ahead in the next contest, New York, by double digits, and though Mr. Sanders was born and reared there, Ms. Clinton has won two U.S. Senate races in the state and is familiar with the tribal politics of New York City, the suburban politics of Long Island and Westchester County, the rural politics of Cattaraugus and Wyoming counties and the state’s Southern Tier, and the regional peculiarities of politics in Buffalo, Rochester, Syracuse, Utica, Troy and Albany.

The challenges are no less formidable for Mr. Cruz, who also faces a classic New Yorker in Mr. Trump.

All of the last three polls put Mr. Trump’s lead over Mr. Cruz at more than 30 percentage points in the state. “Trump is in a good position to win New York because he has an appeal to people looking for radical change,” says Stanley Lundine, a former Democratic House member and lieutenant governor from Bemus Point, on Lake Chautauqua in the western part of the state. “There are a lot of Republicans like that in this state.”

The picture is no brighter for the underdogs in Pennsylvania, which follows New York on April 26 in the parade of primaries. Mr. Trump’s lead here is 9 points, according to this week’s Quinnipiac poll, which also shows that only 7 percent of Republicans are undecided. Ms. Clinton’s lead in Pennsylvania is 6 points.

For Republicans, the question increasingly is whether a plurality of convention votes will be enough to earn a candidate the nomination, or whether a majority, as required in current party rules, will be necessary. Mr. Trump argues the former, Mr. Cruz and Gov. John Kasich of Ohio the latter. Mr. Cruz and Mr. Kasich are counting on an open convention to discard Mr. Trump and open a route for them to the nomination.

But polls repeatedly show that Republicans, who almost certainly won’t provide a majority of delegates to Mr. Trump, feel ardently that the strongest performer in the party’s primaries and caucuses should get the nomination. Mr. Trump, having helped to pump up turnout this year, will likely win more votes than any Republican has ever won in primaries and caucuses, but recall that Ms. Clinton made the same claim for the Democrats in her 2008 presidential race and still wasn’t nominated.

Some two-thirds of Republicans believe that if the party nominates a candidate other than Mr. Trump, it should be someone who ran. That is sobering for party leaders who have been floating the notion that House Speaker Paul Ryan might be a compromise unity candidate. Mr. Ryan in that case would face a 13-week campaign while Mr. Cruz is completing his 13th month of campaigning.

More than a century and a half ago, a future president issued a famous dispatch from the Civil War’s Battle of Spotsylvania. “I propose to fight it out on this line,” Ulysses S. Grant wrote, “if it takes all summer.” His Republican legatees might say the same thing now.

David Shribman, a Pulitzer Prize winner in journalism, is executive editor of the Pittsburgh Post-Gazette.

Comment by clicking here.