UPDATE: Although Sen. Hillary Clinton officially endorsed her Democratic Party rival Sen. Barack Obama on Saturday, mentioning his name 14 times in her speech, the gesture was seen as lacking enthusiasm by some observers.

"She didn't pretend to like or admire Obama," Michael Goodwin wrote in the New York Daily News. "She didn't pretend she believes he would be a great President. She didn't say he was right on the issues. She never said he'd be a good commander in chief or would keep America safe."

Last Tuesday, as the final Democratic presidential primary votes were counted, Sen. Hillary Clinton was on the verge of conceding the race to Sen. Barack Obama.

Clinton was prepared to announce that Obama had achieved the needed number of delegates to win the nomination, campaign officials said, all but ending her White House bid.

The next step was for her official endorsement of her rival. She may gain leverage by waiting: either to secure the vice-presidential slot for herself or to pay off her campaign debt. 

So how did her endorsement speech compare to how how some other ex-candidates did it?

New Mexico Gov. Bill Richardson, soon after departing the race:

Former Sen. John Edwards, who waited until the Obama-Clinton contest became clearer:

On the GOP side, former New York Mayor Rudy Giuliani endorsed Sen. John McCain the same day he dropped out of the Republican race:

Mitt Romney was quick to endorse McCain as well, coming only a few days after announcing he was suspending his campaign:

While not a candidate, Oprah Winfrey's endorsement in Iowa may have proved crucial in the race thanks to her popularity with women voters. If not Hillary, then Vice President Oprah?

Eight years ago, McCain waited months to endorse his then rival George W. Bush for the Republican nomination. McCain's reluctant endorsement is shown in this CNN report from May 2000:

Related post: Candidates: Watch Your Language!

(Original post on June 3 was before Clinton left the race.)