Sweeping primary victories Tuesday in New York by Hillary Clinton and Donald Trump signal the pair will likely win their respective party nominations for president, says a Duke political scientist.

Clinton’s victory, in particular, means the race against fellow Democrat Bernie Sanders is “virtually over.”

“Hillary Clinton’s strong win in New York shows three things: First, Bernie Sanders is very unlikely to be able to stop her from winning a first ballot victory. The race is virtually over,” says political science professor John Aldrich. “Sanders’ recent winning streak was generated out of mostly small states and mostly caucuses. This win demonstrates that Clinton will have received substantially more support from Democratic voters by the end of the primary season.”

Aldrich adds that the two have “settled into clear voting coalitions in the electorate,” and neither shows any signs of being able to cut significantly into the other’s base of support.

Also, Clinton owns the support of traditional Democratic bases — especially among minority voters — which will serve her well in next Tuesday’s string of Eastern nomination contests, which include Pennsylvania and Maryland.

“It is hard to see, if she does well as it seems, how Sanders can maintain any claim of holding ‘momentum.’ Neither shows any signs of expanding their base, and momentum means building on one’s current strength to reach greater levels of support,” says Aldrich, who specializes in American politics and behavior and political institutions.

For Republicans, Trump’s “really substantial win” in New York means he is likely to win a first-ballot nomination. “Either because he will simply win an outright majority in the primaries and caucuses or because he will come so close that, regardless of Ted Cruz’s best efforts, Trump will be able to win enough of the remaining delegates to put him over the top,” Aldrich says.

“Trump’s win in New York also demonstrates that Cruz really is perceived as a real conservative and cannot make any traction even among more moderate Republican conservatives,” he says. “It implies that he would have a very difficult time avoiding what might be a very large defeat, were he nominated. John Kasich also showed an inability to generate any significant expansion of support, even when there are large numbers of Republicans who should be ripe for his appeal.

“Trump shows great strength in winning strong victories in states in which Republicans are unlikely to win in the fall. This suggests that next week will be good for Trump, bad for Cruz.”

Looking beyond the nominating contests, if the presidential candidates are Clinton and Trump then the results from New York suggest that Trump can get support and perhaps enthusiasm in states he is likely to lose, and do less well elsewhere.

“To defeat Clinton, he will need to expand his base but, even more, generate really disproportionate turnout among his followers, so that, while they may be large minorities in key states, they turn out so much more that he can have a chance at winning some of the battleground states.”

“Clinton has the simpler task. She needs to hold her own and get them to the polls in good but not so great numbers as Trump must achieve.”