DENVER — Democrats and the country got an early look at their ticket when Barack Obama, just hours after being officially nominated to be the Democratic presidential candidate, joined his vice presidential pick, Sen. Joseph Biden, onstage Wednesday night promising to “take America back.”

Obama strolled casually onto the stage following Biden’s (D-Del.) remarks, after a brief introduction from Biden’s wife, Jill, who notified the crowd that they were about to receive a “surprise guest.” The massed delegates erupted in delight and exchanged their red “Biden” signs for white ones reading, “Obama-Biden.”

The elder senator tried to share some of his perceived blue-collar bona fides with Obama, referring to him at one point as “the great American story.”

“Barack Obama and I took very different journeys to this destination, but we share a common story,” Biden said.

Biden’s personal story about the loss of his first wife and daughter in a car accident, told by way of a video introduction and by his son Beau, moved many in the crowd to tears, including Michelle Obama, the nominee’s wife.

But the tears turned to excitement as Biden criticized the Bush administration and McCain’s policies on both the economy and foreign policy.

Biden listed what he sees as the shortcomings of McCain’s vision, repeating the refrain: “That’s not change. That’s more of the same.”

At one point, Biden said “George” instead of “John,” excusing it as a “Freudian slip.” And he used a key theme of Obama’s, saying that it was the Illinois senator’s opposition to the war in Iraq that showed good judgment, not McCain’s call to war.

“John McCain was wrong,” Biden said several times. “Barack Obama was right.”

While the Delaware senator did talk about how he and McCain are good friends and he praised the Arizona Republican’s service, Biden said that “these times require more than a good soldier — they require a wise leader.”

“A leader who can deliver change,” Biden said, “the change everybody knows we need. Barack Obama will deliver that change.”