Trump's 'tidal wave' of victories keeps Republican nomination within reach

Donald Trump declared himself the Republican Party's presumptive nominee Tuesday night after a clean sweep of five states that nowforces his rivals to pin their hopes on Indiana next week to stop him.

"As far as I'm concerned, it's over," Trump told supporters in New York after claiming victory in Pennsylvania, Maryland, Connecticut, Delaware and Rhode Island.

It's not over yet, asTrump doesn't have the 1,237 delegates he needs to clinch the nomination ahead of the July convention in Cleveland, but he took a giant step toward hitting that target. He's trying to reach it by the time the primary season ends with California on June 7.

Tuesday's primaries pushed Trump up to around 950 delegates, according to The Associated Press, padding his lead over Texas Senator Ted Cruz and Ohio Gov.John Kasich, and putting him well on his way to the nomination.

• Hillary Clinton wins 4 states, Trump sweeps all 5
• Ted Cruz-John Kasich deal may hurt more than just Trump

William Galston, a senior fellow at The Brookings Institution, a Washington-based think-tank, agreed with Trump's assessment about what the victories signify,and described them as "a tidal wave."

"People I think after tonight will begin to think of Trump as the inevitable nominee," said Galston, a veteran presidential campaign organizer.

Odds go up Trump's the nominee

Galston said he wouldn't rule out the possibility that the anti-Trump forces will put all hands on deck to slow him down in Indiana's primary on May 3, but given the haul of delegates he won Tuesday, Trump gave himself some breathing room.

"It may be that coming out on top in the popular vote in Indiana isn't quite as essential now as it was 24 hours ago," said Galston. "Tonight substantially increases the odds that he will be the nominee and if he prevails in Indiana, I don't think there is any way that anybody can do anything in the months in between Indiana and California to stop it."

Coming off his huge win in his home state of New York last week, and now with five more wins under his belt, Trump's back-to-back blowouts boost his campaign's confidence and take steam out of the "Stop Trump" movement.

"This victory by Trump gives him added momentum which I don't think you can exaggerate," said G. Terry Madonna, director of the Center for Politics and Public Affairs in Lancaster, Penn.

"It is going to make it much more difficult to stop him from getting the nomination, even if he does fall 25 to 30 votes short of the magic majority," Princesaid.

The way the delegate math is adding up, Cruz and Kasich now have no chance of winning the nomination before the convention in Cleveland. Their focus is on blocking Trump from getting it, forcing a contested convention, and hoping he doesn't reach a majority on the first ballot. The theory is if there is a second ballot, a majority of delegates would then vote for either Cruz or Kasich, not Trump.

Trump's victories Tuesday, however, keep that magic 1,237 number well within his reach.

"Given tonight, he is on target and he has a chance to get it," said Madonna.

Indiana key to blocking Trump

To continue on that path and to keep it clear, Trump will have to do well in Indiana. There are 57delegates at stake there, and Trump has his work cut out for him to win them.

Conservative Indiana is more friendly territory for Cruz, which is why he and Kasich came to the agreement that Kasich would give up campaigning there and leave it to Cruz to peel delegates away from Trump. Cruz, in turn, agreed not to compete with Kasich in Oregon and New Mexico.

Trump called their alliance desperate and pathetic,and political analysts are calling it too little too late.

"You didn't have to be a rocket scientist to figure out this is what they were going to need to do," said Larry Ceisler, a veteran political observer who has worked on presidential campaigns and now works in public affairs. "They should have done this a few weeks ago."

The results in Indiana will determine whether the strategy pays off, and for Cruz and Kasich, it must if they are to prevent Trump from clinching the nomination.

"If they can't stop Trump there, I just don't see them stopping him," said Ceisler.

Their alliance showed signs of fracturing almost immediately and observers say it could actually help Trump, not hurt him. It's playing into his narrative that the establishment wing of the party is trying to suppress the will of voters.

"That was a marriage not made in heaven," Madonna said of the Kasich-Cruz cooperation.

After Indiana, four more states vote throughout May, before the biggest prize of the season, California, with 172 delegates at stake. Several other states also vote June 7.

Clinton leaps ahead, Sanders staying in

On the Democrats' side, Hillary Clinton didn't get a clean sweep like Trump, but she similarly took a leap forward to the 2,383 delegates she needs for her nomination.

There were 384 pledged delegates at stake, and she won the states with the biggest jackpots, Pennsylvania and Maryland, as well Connecticut and Delaware. Sanders claimed Rhode Island. Delegates in the Democratic races are awarded proportionally.

The delegates Clinton racked up Tuesday pushed the nomination further out of Sanders's reach and makes it anuphill climb for him to catch up in the remaining primaries.

Clinton now has 1,622 pledged delegates, according to The Associated Press, along with 519 superdelegates, who are under no obligation to back Clinton at a convention and can change how they vote.

"What a great night!" Clinton declared to supporters in Philadelphia, where the convention will be held in July.

She delivered a speech that sounded much like she is ready to pivot to the general election. She told the crowd that she would be back in Philadelphia with the most votes and pledged delegates and she spoke of unifying the party.

"Whether you support senator Sanders or you support me, there is much more that unites us than divides us," she said.

Sanders, speaking earlier in the night in West Virginia, indicated he won't bow to any pressure for him to drop out.

His campaign also issued a statement saying he is in the race "until the last vote is cast."