Here’s what you need to know:
• Aiming for sweeps.
Hillary Clinton and Donald J. Trump are looking to take a decisive advantage after today’s elections in Connecticut, Delaware, Maryland, Pennsylvania and Rhode Island. At stake are 172 delegates for the Republicans and 462 delegates for the Democrats.
Here’s what to watch for today.
It looks like the deal between Ted Cruz and John R. Kasich to coordinate against Mr. Trump is already faltering. Our interactive delegate calculator lets you simulate how the nomination process could unfold.
• Pre-election victory for the G.O.P.
A federal judge has upheld North Carolina’s Republican-backed voter identification law — it requires voters to present one of six forms of documentation — despite civil rights groups’ protests that it unfairly targets minorities. The ruling, in a swing state, could play a role in deciding the presidential election.
• Foreign policy lessons.
President Obama’s trip to the Middle East and Europe showed that he has accepted a more incremental approach in certain situations.
In Europe, he gently urged allies to do more to defend themselves and to solve their own problems, and he told Arab countries to rely less on the U.S. for their security.
• Somber anniversary.
Thirty years ago today, an explosion at the Chernobyl nuclear power plant in Ukraine released far more radioactivity than the atomic bombs dropped on Japan did, forcing the resettlement of more than 350,000 people. The final stage of the cleanup may begin next year.
• Twist in Deflategate case.
The Patriots’ superstar Tom Brady will most likely have to serve a four-game suspension this fall, after a court ruling on Monday, though the panel’s decision can be appealed.
The punishment stems from an N.F.L. inquiry that found Mr. Brady was “generally aware” of a plot to deflate footballs in a January 2015 playoff game. About $20 million have been spent on legal costs, about the same as for Watergate.
• Federal regulators have approved Charter Communications’ deal for Time Warner Cable, creating a broadband and cable television juggernaut at a time when consumers rely on the Internet as a utility.
• Research suggests that globalization and related job losses since the turn of the century have contributed heavily to the bitter political divide in the U.S.
• A velvet rope economy is emerging as companies offer extravagance and exclusivity for the wealthy, stirring up class resentment.
• On the music charts.
Fans are rushing to buy Prince’s albums, and eight of them are in Billboard’s Top 200, including in the No. 1., No. 2, and No. 6 positions.
• Fresh reads.
Among today’s nonfiction releases: “The Jazz of Physics,” which connects music and science; “Off Script,” about campaign miscues that sank presidential bids; and “Her Again,” a biography of Meryl Streep.
(Earlier, we misspelled the book title “American Pharaoh.”)
• On the brink of extinction.
The population of the world’s largest primate, the Grauer’s gorilla, has dwindled to fewer than 3,800 in the Democratic Republic of Congo.
The St. Louis Blues ended the Chicago Blackhawks’ season with a 3-2 Game 7 victory on Monday night. Chicago has won three Stanley Cups in the last six years.
• What to watch.
Scientists investigate how the environment and wildlife have been affected by high radiation in “Life After: Chernobyl” (10 p.m. Eastern, Animal Planet.)
Our TV critic is getting irritated by the growing length of individual episodes, a consequence of the hundreds of original scripted series every year.
• Recipes of the day.
Celebrate asparagus season by preparing some Italian-style, take sloppy joes to another level with these Korean-inspired steps, or try this version ofmatzo brei that might be better than your mother’s.
Despite Mr. Trump’s advantage in delegates, his opponents argue that it is not too late to stop him, an effort that relies on the complex system of rules for choosing convention representatives.
Party conventions have faced those accusations before, with one of the most famous examples occurring in 1960.
Former President Harry Truman resigned as a delegate to the Democratic National Convention, calling the event “a prearranged affair,” fixed to give the nomination to John F. Kennedy.
Although Mr. Kennedy arrived in Los Angeles as the front-runner, having won each of the seven primaries he entered, his selection was not a done deal.
He didn’t reach the necessary vote total for the nomination until Wyoming, the final state scheduled in the roll call, pushed him over the top.
The political jockeying continued to the very end, with the convention floor briefly taken over by nondelegates who had slipped into the hall to support Adlai Stevenson, the Democrats’ nominee in 1952 and 1956.
The top Democratic Party official said the protest was “the best answer to charges of rigging for Jack Kennedy.”