After Cobb was officially nominated, many Nader supporters stormed out. Some sobbed. Others cursed and threw their Green Party posters to the ground.
"This is a dark day," said Robert Nanninga, a delegate from Encinitas, Calif. "We've just nominated a white lawyer with a car salesman's smile. It might as well be a Republican. This is going to be remembered for years to come."
Third-party presidential candidates typically attract little attention and minuscule voter support. But with polls showing a close race between Bush and Kerry, analysts and political leaders took careful note of the Green Party gathering.
"The threat of Nader [as the Green Party choice] was real to the Democrats," said Bruce Cain, director of the Institute of Governmental Studies at UC Berkeley. "In critical states ... his votes could have made a difference. Cobb? No chance."
This year, Nader was endorsed by the Reform Party, which gave him ballot access in seven states, including the battlegrounds of Florida, Colorado and Michigan.
The Green Party convention, which attracted about 1,000 attendees, had something that the Republican and Democratic conclaves lost decades ago -- suspense.
In Saturday's first round of voting, delegates split among 11 different candidates. Most sided with Cobb, Nader or Peter Camejo, a Californian and Green Party activist whom Nader last week tabbed as his running mate on his independent ticket.
After no single candidate garnered a majority vote in the first round, a subsequent slimmed-down list led to delegates giving Cobb about 53% of their votes -- 408 out of 767.
"This says that the Green Party, which Ralph Nader has long considered his, has finally gotten out from under his shadow," said Cobb.
"We wish them good luck, but there are still many Greens who are for Ralph Nader," said Nader spokesman Kevin Zeese. "This is not over for us."
Many delegates and Green Party officials said Nader's decision not to attend the convention in Milwaukee helped tip the balance to Cobb. Nader, who is working on his campaign in Oregon, spoke to delegates via telephone at a rally Friday night.
"It was hard for a lot of people to be sympathetic to him, because they got here -- and he didn't bother," said Marnie Glickman, a Green Party co-chairwoman.
She added that Cobb, a Humboldt County resident, "spent the time and energy to be with us. [Nader] did not."