Gov. Larry Hogan addresses members of the Maryland House of Delegates in Annapolis, Md. Standing behind Hogan is Lt. Gov. Boyd Rutherford. (Patrick Semansky/AP)

Maryland Senate President Thomas V. Mike Miller Jr. ­(D-Calvert) and Democrats from Montgomery County are rallying around Republican Gov. Larry Hogan's $5 billion incentive package to lure Amazon.com and a 50,000-person headquarters to the Washington suburb, but it remains to be seen whether the rest of the Democratic-majority legislature will support the package.

The package, including $3 billion in tax relief and grants and $2 billion in unspecified transportation upgrades, needs to be approved by the General Assembly.

Miller said Monday night that he "fully supports" the plan. "Whether in Baltimore City, Prince George's County or Montgomery County, we need to make it happen," he said. "It's jobs, jobs, jobs and more jobs."

State lawmakers representing Montgomery — all of whom are Democrats — held an emergency meeting Monday evening to discuss Hogan's proposal. They were supportive of the governor's plan, said Del. Shane Robinson (D), chairman of the county's House delegation.

"There's been a lot of talk in Annapolis about bipartisanship, and it's been empty talk, but this is an opportunity to come together to bring many well-paying jobs . . . that otherwise wouldn't be here," Robinson said.

County Executive Isiah Leggett (D), who also attended the meeting with Montgomery lawmakers, said Hogan's proposal was necessary for the county to advance its pitch. County Council President Hans Riemer (D) also applauded the state package but cautioned that officials must consider residents' concerns about increased congestion and housing costs.

"We have a very specific way that we evaluate the cost and benefits, and we don't approve incentives that are not strongly in the benefit of the community and of the county," Riemer said.

Amazon last week released the names of 20 regions in the United States and Canada that it is considering for a second headquarters. The District, Northern Virginia and Montgomery County are among them. D.C. and Virginia officials have revealed little about what they are offering Amazon even after Maryland went public Monday. (Amazon.com founder and chief executive Jeffrey P. Bezos also owns The Washington Post.)

"There's not a lot of utility in bandying numbers about," said Brian Coy, a spokesman for Virginia Gov. Ralph Northam (D).

"We're not allowed to talk about it," said Buddy Rizer, executive director for economic development in Loudoun County, which along with neighboring Fairfax is pushing a site near Dulles International Airport. "The last thing I want to do is be the reason why we don't get the project."

Critics of massive public subsidies say such bidding wars amount to a race to the bottom, which in the case of Amazon will almost certainly intensify as a result of Maryland's offer.

Of the bids that have become public, Maryland's is second only to New Jersey's $7 billion incentive package.

"I'm concerned it might be excessive and it would set a bad precedent," said Tim Bartik, an economist at the W.E. Upjohn Institute for Employment Research who has studied government incentives for economic development nationwide. "How are you going to explain to companies that are only creating 100 jobs or 200 jobs that they can't have the same incentives? It puts pressure on extending the same deal to others."

Stephen J.K. Walters, a conservative-leaning economist at Loyola University Maryland, called the Amazon package "special treatment for people who made it on to the radar screen of political decision-makers."

Hogan, who campaigned on improving the state's business climate, also offered tens of millions in incentives to keep Marriott in Montgomery County, a $20 million grant to keep aerospace giant Northrop Grumman and as much as $317 million for the FBI's stalled search for a new headquarters.

All of those packages pale in comparison to the Amazon offer.

"We overspend on a small number of deals," said Greg LeRoy, executive director of the corporate accountability group Good Jobs First. "We put way too many eggs in a few megadeal baskets, and then we shortchange everything else and everyone else."

Supporters of incentives say they're justified because of the ripple effects of a well-paid ­workforce.

State lawmakers from Montgomery said they will wait until they have seen legislation to create the tax breaks and other incentives before taking a final position. But based on the details released Monday, the leaders of the delegation said most are eager to sign on.

"I haven't talked to anyone who's against it," said Sen. Nancy King (D-Montgomery), chairwoman of the Senate Delegation and a member of the Senate Budget and Taxation Committee.

"What's good for Montgomery County is good for the state," King said. "It's too good to pass up, I think."

Robinson said the debate over the incentive package in the legislature could lead to negotiations about what other jurisdictions want in exchange. "I'm sure other jurisdictions are going to ask for something in return. I certainly would," he said.

Del. Robbyn Lewis (D-Baltimore), blasted Hogan's offer to Amazon in light of the governor's cancellation of a mass transit project in Baltimore nearly three years ago.

"Now he wants to throw away *our tax dollars* to lure Amazon?" she tweeted.

Last week, Miller raised concerns about supporting the Amazon package before other obligations in Baltimore City and Prince George's County were still unfunded. But on Monday, he said he is confident those programs will be funded.

Sen. Edward Kasemeyer ­(D-Baltimore County), the chairman of the Senate Budget and Taxation Committee, agreed the Amazon headquarters would be "a once-in-a-lifetime opportunity," but said he is concerned about committing such a large amount of public dollars to land it.

"Obviously there are other needs in the budget which everyone is going to look at and spending on economic development, a lot of people don't feel is effective," he said.

Democrats competing in the gubernatorial primary to challenge Hogan in November had mixed reactions to the Amazon proposal.

"With any one of these deals, we have to be very cautious not to give away so much that we undermine the quality of life that attracts a business here in the first place," said state Sen. Richard S. Madaleno (D-Montgomery), the only lawmaker running for governor. "You can't give away and undermine our ability to keep that public investment going in order to have that flashy press release and groundbreaking."

James L. Shea, a lawyer and former chair of the University System of Maryland Board of Regents, said Hogan should also work with Virginia and the District "to share the costs and benefits, and to increase the attractiveness of our region to ­Amazon."

Ben Jealous, a former NAACP head and favorite of progressives, said lawmakers should question the long-term benefits of offering a "generous tax package to one of the world's wealthiest corporations."

Alec Ross, a technology entrepreneur, said Hogan's proposal seemed too focused on tax breaks and expanding roads instead of shoring up mass transit and education. Krishanti Vignarajah, a former aide to Michelle Obama, noted recent heating problems in Baltimore schools and said the incentive package must benefit "all Marylanders."

A spokeswoman for Hogan said support for his efforts to woo Amazon should cross party lines.

"The governor has a duty to do everything possible to secure 50,000 jobs and untold billions in economic activity," said spokeswoman Amelia Chasse.

She said it was "unthinkable that anyone who currently represents, or is even dreaming about representing Maryland," would not support "our administration's aggressive efforts to bring home this once-in-a-generation opportunity."

Robert McCartney, Antonio Olivo, Rachel Siegel, Patricia Sullivan and Laura Vozzella contributed to this report.