With superdelegates pushing her over the top, Clinton calls for Democratic unity

LOS ANGELES - Hillary Clinton called for party unity Monday, suggesting it was time for Bernie Sanders to abandon his hard-fought challenge, as six states hold nominating contests Tuesday night, when she expects to clinch the Democratic presidential nomination.

Clinton told reporters in California that Tuesday marks eight years from the day she withdrew from the 2008 White House race, endorsing Barack Obama after a bitter rivalry. Her supporters have said Sanders should look at that as a road map for his own exit from this year's race.

After staying above the fray for months, Obama could endorse his former secretary of state as early as this week, the New York Times and CNN reported. White House press secretary Josh Earnest told reporters the president was waiting for New Jersey and California to vote before weighing in.

Tuesday's voting is expected to clinch the Democratic nomination for Clinton, 68, which would make her the first woman nominated for president by a major party.

Her campaign hopes an expected victory in New Jersey will give her enough delegates to effectively lock up the nomination early in the evening, before the results come in from California, the biggest electoral prize and likely the last to report results.

Although she has won more votes, she has shied away from calling on Sanders to drop out. On Monday, she pointed to her 2008 decision to unite the party and said Democrats needed to do the same to take on presumptive Republican nominee Donald Trump.

'I believed it was the right thing to do. No matter what differences we had in our long campaign, they paled in comparison to the differences we had with the Republicans, and that is actually even more true today,” Clinton said.

Clinton long has been the front-runner to be the Democratic nominee but has faced an unexpectedly tough fight against Sanders, 74, a U.S. senator from Vermont.

An Obama endorsement would come as a welcome boost to Clinton and to Democrats concerned the party needs to turn its attention to campaigning against Trump.