President Obama is relying on fanciful revenue projections to fund his overly ambitious agenda, Jack Welch warned in his latest Business Week column.

America could be reeling from the consequences for years to come, he wrote.

Instead of proposing an honest plan to pay for everything, Obama is inflating revenue projections. His budget assumes GDP will grow faster than in the 70s, 80s and 90s, an unlikely scenario, the former chief of General Electric wrote in his column co-authored with his wife, Suzy Welch.

Competition is tougher because of globalization, and spending will be lower because both companies and consumers are trying to pay down debt, Welch said.

“The result can only be slower GDP growth and a deficit Americans can’t afford, even with the tax hikes ahead, which will further hamper GDP growth and thus revenue,” Welch wrote.

The argument that quick action is needed because an emergency is at hand is silencing debate about long-term effects from cap-and-trade legislation, healthcare and financial regulation.

Colin Powell, the former secretary of state, agreed that Obama’s agenda is too ambitious and too costly.

“I think one of the cautions that has to be given to the president — and I've talked to some of his people about this -- is that you can't have so many things on the table that you can't absorb it all,” Powell told CNN. “And we can't pay for it all.”