(AP) -- Hillary Clinton has reached another delegate milestone: She's now won a majority of delegates from primaries and caucuses.

Her win in California easily put her over the top among those delegates.

It's notable because Bernie Sanders has argued that his White House bid remained viable as long as he stood a chance of winning a majority of pledged delegates. To reach that goal, he would have needed landslide victories in all six states voting on Tuesday. But he won only in North Dakota and Montana.

Sanders has hoped that superdelegates -- party leaders who can back any candidate -- would support him as the stronger general election candidate. But superdelegates have never lifted a candidate to the Democratic nomination when he or she trailed in pledged delegates.

The Sanders campaign has acknowledged that he would be unlikely to flip hundreds of superdelegates now committed to Clinton if he didn't win a majority of delegates from primaries and caucuses.

Based on primaries to date, Clinton now has 2,203 delegates -- or more than half of the 4,051 total pledged delegates -- following Tuesday's contests, in which she also won New Jersey, New Mexico and South Dakota. Sanders has 1,828.

When including superdelegates, Clinton's lead is much bigger -- 2,777 to Sanders' 1,876.

It takes 2,383 to win. Clinton crossed that threshold Monday night to become the presumptive nominee.