WASHINGTON – Donald Trump’s sweep of five Northeastern primaries and Hillary Clinton’s victories in four of the five have moved the 2016 presidential election process to the brink of decision in both parties, and a prospective Trump-Clinton faceoff in November.

Trump’s pickup of 109 convention delegates was a particular blow to his closest Republican challenger, Texas Sen. Ted Cruz, who finished an embarrassing third behind Ohio Gov. John Kasich in four states – Connecticut, Rhode Island, Delaware and Maryland.

The results raised Trump’s total to 954, only 283 delegates short of the majority 1,237 required for the Republican nomination, calling into question Cruz’s earlier declaration that Trump would fall short on the first ballot, necessitating an open convention in Cleveland in July.

The outcome also suggested the futility of the recent deal between Cruz and Kasich whereby Kasich agreed to cease campaigning in next Tuesday’s Indiana primary to help Cruz in the stop-Trump effort, and Cruz agreed to do the same in Oregon and New Mexico to help Kasich.

That arrangement, accurately derided by Trump as “collusion,” already appears to be in shambles.

In the Democratic race Tuesday, Clinton lost only in Rhode Island, to Vermont Sen. Bernie Sanders. Nevertheless she picked up more pledged delegates there, 20 to 13, boosting her national total to 2,151, only 232 short of the 2,383 majority needed in the July party convention in Philadelphia.

Her five-state gain was 272 to 114 for Sanders, who now has 1,338 according to the Politico tracking. It seems only a matter of weeks before she goes over the top.

In the Republican contest, where Trump methodically whittled down the original field of 17 to three with a slashing, insulting assault on all comers, a late stop-Trump effort eventually emerged.

No similarly identifiable stop-Clinton drive among the Democrats has risen, other than Sanders’ more policy-driven “political revolution.”

In the New York primary, won resoundingly by Clinton, hostile rhetoric and tempers flared between the two Democrats, but Clinton thereafter made a distinct attempt to cool the atmosphere. On Tuesday night as after the New York voting, Clinton pointedly repeated “there is much more that unites us than divides us.”

With the GOP stop-Trump campaign already on the ropes, the most hopeful vehicle to halt him remains Hillary Clinton in the general election, in what now looms as the almost certain outcome of the still-ongoing primary season.

Despite some mild Democratic wishful thinking that Sanders might now drop out, he insists he will press on to the end of the primary calendar in June and the late July convention. He argues that Democrats in California, who will choose 172 delegates, deserve a right to have their say.

Trump, for his part, signaled after his five-state Northeast sweep that despite his convention manager’s suggestions that a more moderated and civil Donald would soon emerge, he intended to remain his same bombastic self on the stump.

Pivoting to the now-presumptive Democratic nominee, Trump has already labeled her “Crooked Hillary,” feeding on her email troubles and other allegations of untrustworthiness.

As for his campaign style, Trump marked his latest successes by continuing to blast the Republican nomination process as rigged.

He demonstrated little interest in cozying up the party establishment, but rather suggested he intends to remake it more in tune with the army of the angry he has mobilized over the last year.

On Tuesday night, he surprised a crowd in the Trump Tower lobby in New York by inviting questions from the press that went on at unusual length and civility.

His answers again were notably light on specifics about how he plans to “make America great again,” and he denied that a different Donald Trump was about to emerge for the campaign against Clinton.

In the meantime, what is left of drama in the 2016 primary season as it moves west to Indiana next week and on to Nebraska and the Pacific Coast, is whether it will conclude with the first open convention in 40 years.

And, if so, what will be left of the Grand Old Party.

Editor’s note: Jules Witcover’s latest book is “The American Vice Presidency: From Irrelevance to Power,” published by Smithsonian Books. You can respond to this column at juleswitcover@comcast.net.