Maryland Gov. Martin O'Malley addresses the House of Delegates on the opening day of the 2012 legislative session in Annapolis, Md., on Jan. 11, 2012. (Patrick Semansky/AP)

Maryland Gov. Martin O’Malley lacks clear public support for key budget and tax proposals and a bid to legalize same-sex marriage, underscoring the uncertainty of an ambitious legislative agenda that could shape his legacy and political future.

A new poll by The Washington Post finds that 55 percent of Marylanders approve of O’Malley’s overall job performance, even as half of all respondents say he has accomplished only some or not much during his five years as governor. And a slimmer 41 percent approve of the way he’s handling fiscal issues.

At a time when O’Malley (D) has taken on greater leadership roles nationally for Democrats, the poll reveals significant challenges at home as the clock ticks on his second term and as he pushes arguably his most far-reaching agenda yet in the 90-day legislative session that began Jan. 11.

With the governor set to deliver his State of the State address on Wednesday, the poll found rising but still tepid support for same-sex marriage, which O’Malley has vowed to pass after it failed to clear the state’s heavily Democratic legislature last year.

Overall, 50 percent of those polled support legalizing gay nuptials; 44 percent do not. A majority of African Americans object, with many citing religious beliefs as the basis for their opposition. That rift remains pronounced in the state’s General Assembly, where O’Malley has made little apparent progress in courting additional black lawmakers to tip the balance.

O’Malley’s proposals for broad-based tax increases, which are his first since 2007 and which he contends are necessary after years of cost cutting, have also left Marylanders with decidedly mixed views: Fewer than half support even a modest increase in the gas tax to fund more transportation projects, a proposal O’Malley has floated but not formally introduced.

When asked how they feel about an increase of 10 cents per gallon or higher — in line with what lawmakers expect O’Malley to propose — opposition swells above 70 percent and across a range of income levels.

Half of Marylanders also oppose another plan that O’Malley has argued is necessary to improve the state’s infrastructure: doubling collections of the so-called flush tax, a fee on water and septic bills used to modernize waste-water treatment plants.

And fewer than four in 10 support O’Malley’s plan to shift a share of teacher pensions from the state to the counties, a key provision in his plan to balance the state’s projected $1 billion shortfall.

A tough sales job

In public appearances in Maryland, O’Malley has acknowledged that he is asking lawmakers to make several tough votes this year to balance the budget and invest in infrastructure — and that his agenda is “not an exercise in popularity.”

Marylanders are more receptive to some O’Malley initiatives, the poll found.

Fifty-six percent support raising income taxes on those making six figures or more — roughly one-fifth of taxpayers. The plan, which is another part of O’Malley’s effort to balance the state budget, would limit personal exemptions and cap personal deductions for those making $100,000 or more.

Support for the idea grows considerably — to nearly three-quarters of Marylanders — if the threshold for those affected is raised to incomes of $250,000 or more. Some leading lawmakers have started saying that they should move away from O’Malley’s proposal and aim at higher income levels.

Higher bills for wind power?

A majority — 55 percent — also support an O’Malley initiative to jump-start the offshore wind-power industry in Maryland, even if that means small increases in utility bills, the poll found.

Starting in 2017, under the governor’s plan, ratepayers would begin paying about $2 more per month to subsidize generation of a power plant’s worth of offshore wind power.

The plan has support from environmentalists, steel workers’ unions and others, but it remains a tough sell among lawmakers, given O’Malley’s many other proposals that would all hit state residents in the pocketbook.

The poll was conducted by telephone Jan. 23-26 among a random sample of 1,064 Maryland adults. The results have a margin of error of plus or minus 3.5 percentage points.

The numbers suggest that O’Malley has a major sales job ahead of him this session if he is to pass the bulk of his agenda.

Some Democrats have questioned whether O’Malley, who is serving his second year as chairman of the Democratic Governors Association, is focused enough on building support for his initiatives. During the first couple weeks of the session, O’Malley has taken two overnight political trips, to South Carolina and New York, at a time when legislators are still digesting his budget and legislative priorities.

Even for Marylanders who approve of O’Malley’s performance, his plans are a lot to stomach.

Bill Robinson, a Democrat who lives in Charles County, said he thinks O’Malley has done a decent job. With a wife who is an educator, Robinson, 57, said he particularly appreciates O’Malley’s commitment to schools.

Given the state’s budget challenges, Robinson said he could understand raising income taxes on high earners. But Robinson, a telecommunications network engineer who works in northern Prince George’s County, said he is far less enthused about the prospect of higher gas taxes.

“I commute pretty far, and I burn a couple of tanks of gas a week,” he said. “I wish we would look at other ways to balance the budget.”

Jane Sullivan, 63, a substitute teacher in Montgomery County, said she thinks that “most of the things” O’Malley has been doing “are pretty good, given the economic climate we’re in.”

She likes O’Malley’s proposal to raise income taxes on six-figure earners and wants to see offshore wind power developed, although she isn’t sure ratepayers should shoulder the costs. She is against a hike in the gas tax, however.

“I don’t mind paying for things that are useful, but I object to things that cost a fortune and seem like a waste,” said Sullivan, a registered Democrat who lives in Germantown.

Others suggested that O’Malley should consider tweaking his plans.

Marian Jenkins, 70, a retired Agriculture Department employee in Waldorf, said a salary of $100,000 isn’t as much as it used to be, especially with children, and suggested targeting earners somewhere between $250,000 and $1 million.

“They can pay more,” said Jenkins, a Republican. “Basically, I agree with Warren Buffett: A secretary shouldn’t pay more than a millionaire.”

Jenkins’s main gripe with O’Malley’s agenda, however, isn’t his proposed tax increases, but his support for same-sex marriage. “I guess I’m too old-fashioned,” she said.

Same-sex marriage battle

Same-sex marriage is one issue on which public sentiment could mean more than most.

Advocates on both sides of the issue expect that if a bill passes, opponents will make use of a provision in the Maryland Constitution that allows residents to petition just-passed laws to the ballot.

That would set the stage for a November statewide vote on whether Maryland should join the District and six states in allowing gay nuptials.

Maryland voters are already slated to decide another hot-button issue: whether to keep a law on the books to allow certain undocumented immigrants to qualify for in-state college tuition. To quality for the lower rate, students must graduate from a state high school, and their parents must file income tax returns.

The Post poll found that 58 percent of respondents support the law, which passed last year with O’Malley’s backing, while 41 percent are opposed.

Abolishment of the death penalty, another social issue O’Malley has championed in recent years, did not fare as well in the Post poll.

A 52 percent majority favors the death penalty for people convicted of murder, down from 60 percent in 2007 and 2010. The dropoff in support among political independents has been particularly steep.

Still, the poll found in a separate question that 57 percent think the death penalty should remain on the books for the most terrible crimes, while 40 percent favor its repeal.

O’Malley unsuccessfully championed a bill to repeal the death penalty in 2009. Instead, lawmakers tightened evidentiary standards in capital cases.

Aides say O’Malley would still like to see the death penalty abolished, although that goal is not part of his formal legislative package this year.

When asked what issue Marylanders would like to see the governor and lawmakers work hardest on this session, crime ranked pretty low.

The most popular choice is the state economy, cited by 32 percent, while another 16 percent said the state budget. Public education is the choice of 22 percent.

Although a majority approve of the job O’Malley is doing, many fewer Marylanders have bought into the notion that he could win higher office. Only one-quarter of voters said they think O’Malley would make a good president. Among Democrats only, that rises to about three in 10.

Polling manager Peyton M. Craighill and polling analyst Scott Clement contributed to this report.