The New York Primary: Why Trump’s win is worth more than Hillary’s win.

We have come to the point in the race for the Democratic and Republican nominations where winning a state is less important than winning delegates. This was the case last night in New York. Hillary Clinton and Donald Trump won convincing victories in their home states, but what really matters is how many delegates they won. We won’t know that for sure for a while. Votes are reported by counties; delegates are awarded by congressional districts, and once the votes are in they have to be mapped onto congressional districts. Nonetheless we can say this for sure—Donald Trump’s big win will be worth more than Hillary Clinton’s big win.

Here’s why.

The two political parties have different philosophies about how to award delegate slots to their presidential candidates. Between 1968 and 1988 the Democratic Party fought over how they should award delegates. Reformers generally fought for proportional representation while party “regulars” or the party establishment tended to favor systems that gave more delegates to winners than to losers. In 1988, the Reverend Jesse Jackson ran up some impressive victories and went into the Democratic convention with over 1000 delegates—not enough to take the nomination from Governor Michael Dukakis but enough to make trouble for him. And so, to pacify Jackson, Dukakis agreed to a convention rule that would force every state to use proportional rules for the 1992 convention. And the rule has been in place ever since.

The Republican Party was never very fond of proportional representation and favored winner-take-all systems. But in an effort to keep the nomination from being won too early, and to keep states from moving earlier and earlier in the year, the Republican Party adopted a system for 2012 that kept early states from using winner-take-all rules. So today, each Republican state party chooses its own rules according to how early they go in the nomination season. Their rules range from proportional systems similar to the Democrats’ to systems that become winner-take-all when a candidate crosses a certain numerical threshold to systems where the winner of the state wins all the delegates.

The rules on how to award delegates shape the nomination race in each party in different ways. Consider, for instance, the situation eight years ago on March 5, 2008. On that day Senator John McCain had clinched the GOP nomination by winning 100 percent of the delegates in Ohio and Vermont and practically 100 percent in Texas. On the other side of the aisle, the race was still on. Although Hillary Clinton had won a solid victory in Ohio—her 10 point victory netted her only 75 delegates and Barack Obama won 66 delegates.

Without getting into too much math, the best way to understand the system is to understand that the Republican rules, which include many winner-take-all states, reward winners by boosting their share of the delegate count relative to their share of the votes. On the Democratic side the rules work exactly the opposite. In close races, the loser can often win the same number of delegates as the winner. As the political strategist and rules expert Harold Ickes wrote to the Clinton campaign in a 2008 memo that didn’t get enough attention: “Proportional representation cushions on the downside and limits the upside and affects even numbered delegate districts differently than odd numbered delegate districts.”

Which brings us to the New York primary. When all the votes are in and distributed by congressional districts, Trump’s impressive victory is likely to get him almost all of New York’s Republican delegates while Hillary Clinton’s equally impressive victory is likely to get her a far smaller share of the total delegates from New York. While both winners came in with about 60% of the vote, it looks like Trump will win almost all of New York’s 95 convention delegates (probably 90) while Hillary Clinton will get about 129 of New York’s 247 delegates while Sanders will probably get 98 delegates.

As we move into the final act of the nomination season the delegate count will tell us a great deal about whether the conventions will be contested or be the sort of boring affairs we’ve gotten used to over time. Although Trump did his best to look more presidential last night—referring to his opponents as “Senator Cruz” and “Governor Kasich” (as opposed to coming up with some sort of insult)—he continued to call the system rigged and still faces an establishment that sees him as trouble at the top of the ticket. On the Democratic side, the establishment is more than comfortable with Clinton at the top of the ticket but the continued presence of Sanders in the race and the allocation rules described above mean that Clinton has to continue to work hard to win the bulk of the pledged delegates. The race goes on.

Elaine C. Kamarck is a Senior Fellow at the Brookings Institution and author of Primary Politics: Everything You Need to Know about How America Nominates Its Presidential Candidates. She is a superdelegate to the Democratic convention.