Obama extends oliver branch

Bearing those high stakes in mind, Obama has been extending an olive branch to Clinton in recent weeks.

On Sunday, he was quick to congratulate Clinton's win in Puerto Rico.

"I just got off the phone with Senator Clinton. She's going to win Puerto Rico and I wanted to congratulate her for that," Obama told supporters in Mitchell, South Dakota.

"Senator Clinton is an outstanding public servant," he said.

"She has worked tirelessly in this campaign. She has been a great senator for the state of New York, and she is going to be a great asset when we go into November to make sure that we defeat the Republicans," Obama added.

Earlier news reports said Obama had ordered his staff members to reach out to Clinton supporters and even privately offered her a cabinet post, a report Clinton denied later.

For the moment, Clinton showed no sign to voluntarily quit the race, though she was reportedly considering her future plans.

It's noteworthy that her campaign has recently stopped attacking Obama.

News reports said that it's obvious that Clinton would be forced to leave the race at some point, but she is leaving all the options open.