Sen. Zell Miller announced Thursday that he will be a lead co-sponsor of President Bush's $674 billion economic plan, making him the first Democrat to throw his support behind the economic stimulus package.

Miller of Georgia gave his endorsement when he introduced the president Thursday at Harrison High School in Atlanta, where Bush was delivering an economic speech.

While the support is not a huge surprise — Miller is a strong advocate of tax cuts — he still could give a boost to the president, who has been beating back Democratic charges that it will only help the wealthy.

Miller, a popular former governor who has said that he won't seek re-election in 2004, also was a co-sponsor to the president's proposed $1.6 trillion tax cut package in 2001. That final 10-year, $1.3 trillion package was also supported by centrist Democrats John Breaux of Louisiana and Ben Nelson of Nebraska, who have not endorsed the current plan.

Breaux has been open about his reservations about the elimination of double taxation on stock dividends, the bulk of the president's plan, and has said several times that in its current form, the president's proposal could not pass the Senate. He said that any economic plan must be modest, temporary and targeted in order to pass and he is "not sure" the president's plan meets those goals.

Nelson met recently with Treasury Secretary John Snow, where he made it clear that while he supports the principle of the dividend tax cut as part of a reform package, he does not believe that's what's needed right now in an economic stimulus package. Nelson told Snow he believes the number one priority right now should be stimulus and "this tax proposal is not stimulus."

Miller has often backed the administration in key fights, economic and otherwise, and has rejected criticism from other Democrats that the 2001 cuts didn't target middle-class Americans most likely to spend the extra money and stimulate the economy.

"Who are we to pick and choose and select and cull and single out among our taxpayers?" Miller said at the time. "Who are we to play eeny, meany, miney, mo with our taxpayers?"

After Bush's State of the Union address earlier this month, Miller released a statement announcing he would vote for every tax cut that makes the Senate floor. It seemed clear then, although he didn't acknowledge it, that he was referring to the stimulus plan.

"Like with my grandchildren, I love them all," he said. "However, I do wish that spending cuts came along with the tax cuts. And if none are there, I will offer some myself."

Fox News' Julie Asher and The Associated Press contributed to this report.