The Note: Acela Primary Primer

— -- NOTABLES

--5 STORYLINES TO WATCH: The so-called "Acela primary" launches today, bringing voters to the polls in five Northeastern states. Ballots will be cast in Pennsylvania, Connecticut, Rhode Island, Maryland and Delaware, largely finishing up most of this election's primaries in the region. Here are five of the most important storylines to keep an eye on as voting unfolds, courtesy of ABC’s MEGHAN KENEALLY: http://abcn.ws/1Wnx1np WHAT'S AT STAKE TODAY with ABC’s ALANA ABRAMSON: http://abcn.ws/1T1zwGj

--A CLOSER LOOK AT THE PENNSYLVANIA PRIMARY:  Pennsylvania is the biggest delegate prize out of the five Northeastern states voting today. ABC’s VERONICA STRACQUALURSI has more on the dynamics of the primary in the Keystone State: http://abcn.ws/1QxqmA3

--TODAY ON ‘GMA’ -- SANDERS VOWS TO 'FIGHT ALL THE WAY TO PHILADELPHIA’: Democratic presidential candidate Bernie Sanders today vowed to focus on real issues and stay in the race all the way to the summer convention, ABC’s MARYALICE PARKS reports. "The election is not over yet," he told "Good Morning America.” He added: "We're going to fight all the way to the Philadelphia convention and we're going to win as many delegates as we can and we believe we do have a path toward victory." Asked about the real prospect of opponent Hillary Clinton's reaching the number of votes she needs to secure the nomination after the June California primary, Sanders said, "We are going to fight through California and then we see what happens." http://abcn.ws/24hl0mb

--ANALYSIS -- ABC’s RICK KLEIN: The division part of “divide and conquer” – that Donald Trump’s rivals have down. As for the rest… the John Kasich-Ted Cruz union had hardly been announced before Kasich and Cruz quibbled with its terms and ultimate meaning. (Kasich doesn’t want his supporters to vote for Cruz in Indiana? Cruz says Kasich suspended his Indiana campaign – but isn’t talking about Oregon or New Mexico?) Putting aside the practical challenge of convincing tens of thousands of Republican voters to support not their favorite guy but some other guy – all to block a third guy – there’s a serious ideological rift between the two camps that are trying to team up. Many Kasich supporters thing Cruz is every bit as much of the problem with their party as is Donald Trump. Similarly, many Cruz supporters think the GOP has made too many mistakes with Kasich-like candidates. You know who is comfortable talking about the new alliance? Donald Trump. It says something that the strategy being employed by his rivals fits Trump’s message much more comfortably than it does Kasich’s or Cruz’s.

YESTERDAY ON THE TRAIL with ABC’s VERONICA STRACQUALURSI and PAOLA CHAVEZ

CRUZ HAS HEATED EXCHANGE WITH DONALD TRUMP SUPPORTER. Outside an Indiana ice cream shop Monday, Texas Sen. Ted Cruz stepped off his campaign bus and was almost immediately confronted by an angry Donald Trump supporter. Kathy Hiel questioned Cruz about the delegate process, accusing him of rigging the system. ABC’s JESSICA HOPPER reports, The contentious exchange ended with Hiel saying Cruz isn’t a natural-born citizen and Cruz saying that if Trump had been confronted by a voter challenging him, the Trump campaign would have threatened the voter with violence. WATCH: http://abcn.ws/26pCoHg

TRUMP LAUNCHES VERBAL FOOD FIGHT OVER JOHN KASICH’S ‘DISGUSTING’ EATING HABITS. A verbal food fight is breaking out between Donald Trump and Ohio Gov. John Kasich. While Trump had coined nicknames and thrown insults at other rivals like Sens. Ted Cruz and Marco Rubio far earlier on the campaign trail, the real estate mogul went low and attacked Kasich's table manners Monday. "I have never seen a human being eat in such a disgusting fashion," Trump said of Kasich at an event in Rhode Island. "I’m always telling my young son Barron, I’m saying and I always do it with my kids. ... I would say, 'Children, small little bites.'” ABC’s MEGHAN KENEALLY and BEN GITTLESON have more. http://abcn.ws/1pzhpzX

CRUZ, KASICH SEND MIXED MESSAGES AFTER AGREEING TO TEAM UP AGAINST TRUMP. The day after Republican presidential candidates Ted Cruz and John Kasich announced they would coordinate their efforts against GOP front-runner Donald Trump in three upcoming primary contests, the two sent mixed messages about how they viewed the deal. ABC’s BEN GITTLESON writes, Kasich said he would not encourage his supporters in Indiana to vote for Cruz, despite his campaign saying last night it would shift its resources to “give the Cruz campaign a clear path” to take on Trump in the state. "I've never told them not to vote for me," Kasich told reporters at a Philadelphia diner, when asked about his Indiana supporters. "They should vote for me." http://abcn.ws/1Sv6Vda

WHAT WE KNOW ABOUT THE CRUZ- KASICH ALLIANCE. The new public alliance between Sen. Ted Cruz and Gov. John Kasich has added yet another surprising element to the ever-evolving presidential race. The two Republican candidates have confirmed that they are being strategic about upcoming races and organizing their efforts to try to avoid competing against one another in certain states, focusing on putting their strongest foot forward against Donald Trump instead. ABC’s MEGHAN KENEALLY reports, Kasich's campaign manager confirmed that they're going to target New Mexico, which holds its primary on June 7, while Cruz said Monday his attention is all on Indiana, which has its primary next Tuesday. Such an approach is undeniably unique, especially given the public nature of their partnership. But whether it will work is an open question. http://abcn.ws/1MT4MeF

NOTED: TRUMP CALLS CRUZ-KASICH ALLIANCE ‘PATHETIC’ AND ‘WEAK’. Republican presidential front-runner Donald Trump attacked his opponents, Texas Sen. Ted Cruz and Ohio Gov. John Kasich, Monday, calling them “weak” and “pathetic” for agreeing to coordinate against him in three upcoming primary contests. "It shows how weak they are," Trump said during a rally in Warwick, Rhode Island. "It shows how pathetic they are.” http://abcn.ws/1pyF57E

VEEPSTAKES

--FIORINA BEING VETTED AS POSSIBLE TED CRUZ VP PICK, AIDE SAYS. Carly Fiorina is being vetted by Ted Cruz's campaign as a possible vice presidential pick, Sarah Isgur Flores, a senior strategist to Fiorina, told ABC News. Flores said no offers have been made at this time, ABC’s JORDYN PHELPS reports. Fiorina, a former Hewlett-Packard CEO and Republican presidential candidate, endorsed Cruz shortly after suspending her own bid for the White House earlier this year. http://abcn.ws/1VydIJc

--THE PROS AND CONS OF PICKING A VP CANDIDATE EARLY. If one of the candidates were to name a vice presidential running mate before they were officially declared the party's nominee, it wouldn't be the first time, ABC’s MEGHAN KENEALLY notes. Unfortunately, it didn't turn out so well when someone tried it before. http://abcn.ws/1rd36Ta

IN CASE YOU MISSED IT

SENATOR LEADS CLINTON SUPPERS IN RENDITION OF ‘SHE WORKS HARD FOR THE MONEY’. If there were an award for the most awkward (yet kind-of amazing) intro speech at a Hillary Clinton rally, it could go to Sen. Tom Carper for his performance Monday at the Democratic front-runner’s event in Wilmington, Delaware. Speaking before Clinton, Carper led the audience in a rendition of Donna Summer’s 1983 hit, “She Works Hard for the Money,” while asking them to “treat her right” in the state’s primary Tuesday. ABC’s LIZ KREUTZ has more. http://abcn.ws/1NM3Ljl

WHO’S TWEETING?

@bgittleson: After explicitly telling his Indiana supporters yesterday to vote for him, Kasich again said today that he wasn't telling them what to do

@JenniferJJacobs: Lost amid reports Cruz-Kasich pact showing "strain" - the deal was never to ask supporters to vote for other guy, just shift time/resources.

@EliStokols: Yep. Basically a clever attempt to mask the fact that both campaigns are running low on funds.

@fran_chambers: Susan Sarandon warns Sanders voters to possible corruption at the polls today

@DomenicoNPR: How is Election Day not a national holiday? My kids' school is closed bc of Election Day yet parents still have to work #campaign2016