CHARLOTTE, N.C. -- The 2012 Democratic National Convention was supposed to reignite the excitement the party experienced in 2008, when then-candidate Barack Obama drew a stadium-sized crowd to an acceptance speech that featured Greek columns and fireworks.

But as President Obama officially launches his bid for a second term this week, there won't be any fireworks, not the real kind anyway.

And television audiences won't see anything close to the 80,000 people who packed what was then Invesco Field at Mile High Stadium in Denver four years ago.

That's because Democratic officials announced Wednesday that they are canceling plans to have the president accept the party's nomination in the 74,000-seat, outdoor Bank of America Stadium. Instead, the president will speak at the much smaller Time Warner Cable Arena, where the rest of the convention was held.

Democrats said the event was being moved indoors because of concerns about the weather.

But the indoor arena seats about 54,000 fewer people than the stadium and critics said the move is evidence that the party couldn't find enough people to fill the bigger venue -- a sign of waning enthusiasm for Obama.

A new ABC/Washington Post poll shows that Obama's popularity has dropped by 7 percentage points since April, to 47 percent, the poll's lowest level for any incumbent president since 1980.

"I think the decision reflects the reality that the magic that filled a stadium in 2008 is gone," said Alex Vogel, a Republican strategist.

Obama campaign officials denied that there were problems filling seats and insist that threatening rains, and not fear of TV cameras panning to empty seats, were to blame for the cancellation. The campaign and party had given away 65,000 tickets for the president's speech at the stadium and had 19,000 people on a waiting list, officials said.

"Our concern was more about turning people away than filling the stadium," Obama spokeswoman Jen Psaki said.

Campaign officials said the president would schedule a conference call or some other event for the thousands of people who had tickets to the stadium event but who will now be excluded from the smaller arena.

The cancelation of the stadium event, a moment Democrats had hoped would recapture the energy of the 2008 event, was just the latest setback for a convention that suffered a series of downgrades, beginning with the Democratic National Committee's decision to shorten the entire event from four days to three.

Charlotte officials were fuming earlier when Democrats scrapped a planned Labor Day festival at the Charlotte Motor Speedway and instead staged a smaller outdoor festival near the convention center.

Convention planners also suffered a backlash from labor unions, a major supporter of past Democratic conventions, which balked at helping with this year's event because the party was holding it in North Carolina, a right-to-work state that bars collective bargaining.

The decision to cancel the stadium left Charlotte officials angry once again. The local newspaper, the Charlotte Observer, blasted organizers in an editorial, saying Democrats had to be aware of the possibility of rain when they scheduled the event for early September.

"It seems to be part of a pattern," by the party, the paper noted. "Make big plans, then scale them back."

The Accuweather forecast for Thursday calls for thunderstorms at 4 p.m. and again at 10 p.m., which could coincide with Obama's speech.