History suggests that these final five states will be anti-climatic. But if the outcome remains unsettled, the survivors will have to navigate California’s massive 172-delegate haul, which awards three for each of the 53 congressional districts, with only 13 for the statewide winner. Like Bush’s Florida and Kasich’s Ohio, Christie’s New Jersey is a true statewide primary, awarding its winner all 51 delegates.

At this point, the remaining candidates will also need to step up their efforts to win over the Republican version of super-delegates—the 168 members of the Republican National Committee, three each from the 56 states and territories. They are the convention’s only guaranteed delegates. While some states bind their RNC members to vote for their statewide winner, no delegates are bound to a candidate for votes on the convention rules, credentials and platform committees. Since RNC members tend to disproportionally end up on these committees, look for the candidates to court them.

By June 8, it will be clear if the leading candidate will have a majority on the first ballot of the convention. If that’s the case, that candidate will spend the next six weeks intensely planning the convention program. If no candidate comes to the convention with a majority of delegates bound to him or her, things will get really wild. The campaigns will have to plan for cutthroat rules fights and credential challenges, and will have to keep close track of the 2,472 delegates in ways no one in living memory has ever had to. The historical uniqueness of the event will draw intense scrutiny in its own right, requiring many sleepless nights as campaigns pivot from a very public primary season to the behind-the-scenes tests of a contested convention.