Like O'Malley and Mikulski, Strickland traversed his state, appearing at rallies and events for the New York senator.
But unlike them, Strickland - a former congressman whose 2006 election ended two decades of Republican dominance in the state capital of Columbus - can claim to have helped deliver an important, diverse state into Clinton's win column.
A television commercial he appeared in was "a straightforward attempt to see whether Strickland can transfer his popularity to Clinton," according to the Columbus Dispatch. "Strickland has a job-approval rating of 56 percent in Ohio, and he is highly regarded by Ohio Democrats."
Other key Clinton victories have come with the assistance of influential political allies.
In Massachusetts, Mayor Thomas Menino of Boston provided a vital counterweight to Sen. Ted Kennedy's high-profile endorsement of Sen. Barack Obama. Menino's troops went to work for Clinton, and Massachusetts went for her, becoming one of the more surprising stories from last month's Super Tuesday contests.
With Pennsylvania looming as the next big contest, Gov. Edward G. Rendell, a former prosecutor and mayor of Philadelphia, is lending his considerable muscle to the effort.
"The Clinton campaign is smart to lean on locals and people who know the state," Rendell said on CNN last week. "Governor Strickland did an enormous job for Senator Clinton in Ohio. And former mayor of San Antonio, Henry Cisneros, did a great job in Texas."
It's a recipe that Hillary Clinton was hoping to replicate in Maryland.
But it didn't work out that way.
The Clinton campaign wanted a boost from O'Malley and Mikulski. A victory here on Feb. 12 would have meant that Obama's 11-contest consecutive win streak never would have started.
Instead, she fell to Obama 61 percent to 36 percent.
O'Malley was elected twice as mayor of Baltimore, a hard-edged city where the sport of politics sometimes eclipses the Orioles in popularity, and he's long been considered an up-and-comer in national Democratic circles. Mikulski is one of the most popular figures in state politics, with an approval rating that has hovered around 70 percent.
So where was the O'Malley machine? Where were loyalists that Mikulski could mobilize? It's a question that some top Clinton advisers are privately asking. They're peeved that Maryland didn't produce.
There's really no such thing as a big city political machine these days, said Herbert C. Smith, a political science professor at McDaniel College in Westminster who has managed and advised campaigns in Baltimore. They went out with the decline of the patronage system, he said.
"Voters are not robots," Smith said. "It presumes this model that Martin O'Malley or any governor can marshal up hundreds of thousands of votes at his command. It's simply not the model of American politics."
O'Malley's political success has come more from good timing, an engaging personality and an ability to raise money than from the backing of large armies of volunteers.
Mikulski is four years removed from her last election, and doesn't face another contest until 2010. So her political machine is at its ebb.
A champion of women senators, Mikulski's endorsement of Clinton comes in part from wanting to help a member of that small club.
During his gubernatorial run, O'Malley got help from former President Bill Clinton, who made appearances in the state. Some political insiders wonder whether O'Malley's support for Hillary Clinton stemmed more from a sense of loyalty and obligation than a true passion for her candidacy.
One of O'Malley's best moments came last June, when he helped Clinton raise nearly a half-million dollars at a Baltimore County fund-raiser. Tickets to the event weren't selling well, but O'Malley hit the phones, salvaging the evening and saving the campaign embarassment.
During the week leading up to the Maryland primary, O'Malley and Mikulski appeared at numerous rallies and surrogate debates. O'Malley, Mikulski and Lt. Gov. Anthony G. Brown each lent two workers to the Clinton campaign for the week, and the three leaders cleared their political schedules for Clinton events.
Still, many Maryland political veterans say that O'Malley, in particular, seemed quiet. Perhaps it was his low approval ratings after a tax-raising special session of the General Assembly - 37 percent in a Gonzales Research poll released last week - that threatened to hinder Clinton more than help her.
His top political people weren't available to lend out. O'Malley's gubernatorial campaign manager, Josh White, is no longer in state government, having left his position as head of intergovernmental affairs to become a lobbyist. His top spokesman, Steve Kearney, is setting up a public affairs shop in Baltimore.
Maryland Attorney General Douglas F. Gansler, a co-chairman of Obama's state campaign, said there was very little that Mikulski, O'Malley or anyone else could have done to help Clinton in Maryland.
The state's demographics - a black population of nearly 30 percent and a high rate of wealthy, well-educated residents - heavily favor Obama,
"To blame Governor O'Malley for the shortcomings here in Maryland would be myopic," Gansler said. "It's really who the candidates are."
The Maryland, Virginia and District of Columbia primaries came a week after Super Tuesday. Many analysts note that the Clinton campaign appears not to have developed an effective post-Super Tuesday strategy, thinking the contest would be over.
The Clinton campaign didn't have weeks to hone its message, as it did for Ohio and Texas.
"We did the very best we could, given the resources the national campaign was able to provide just five days after Super Tuesday," said Rick Abbruzzese, an O'Malley spokesman.
If Clinton wins the nomination and the presidency, it's not hard to imagine a position for O'Malley in her administration. He may be interested in, say, homeland security or environmental protection.
But if he got those jobs, it would be because of his abilities and loyalty, not because of how he delivered votes during the primary.
A reward for that kind of performance would go first to Ted Strickland.