Both are Republicans.
Both have an air of youthful vitality.
Both have regular-guy personas despite prep school and Ivy League backgrounds.
Both have nice-guy images that belie an ideological stubbornness on many political issues.
And, perhaps most importantly, both remain popular despite widespread dissatisfaction with the job they are doing.
For President George W. Bush - who probably didn't wear his cowboy boots at Phillips Andover or Yale - that popularity was proven in handily winning the last election despite an electorate that had serious doubts about his leadership of the country.
For Maryland Gov. Robert L. Ehrlich Jr. - a graduate of Gilman School and Princeton University - that popularity showed up in a recent poll commissioned by The Sun: His job approval rating was 54 percent, though few gave him high marks on specific issues.
"People like Bob Ehrlich," says Tom Schaller, a political scientist at the University of Maryland, Baltimore County who is active in Democratic causes. "He's just plain likable."
Many say the same is true of Bush.
"Everybody thinks Bush is a nice guy," says Matthew Crenson, a political scientist at the Johns Hopkins University.
Ronald Walters, director of the African-American Leadership Institute at the University of Maryland - who helped run presidential campaigns for Jesse Jackson - says this explains what happened in November's election.
"All of the traditional wisdom that political scientists live and die by was thrown out the window," Walters says, pointing to polling numbers and a voter registration boom that should have been certain indications Bush was headed for defeat.
"When you ask voters why that didn't happen, they said it's because they like the guy," Walters says.
Schaller says that presidents and governors have one important thing in common - they are both the head of state and the head of the government, jobs that are separated in many other democracies.
"Bush and Ehrlich are very good at, and very clearly enjoy, being head of state," Schaller says. "What is less clear is if they are willing to do the work of being head of the government."
Voters are attracted to people who are comfortable in these very public offices, which is clearly not the case with many candidates who seem to take on the burden of office out of some moral obligation.
"He likes being governor," Schaller says. "People can tell that, people can tell somebody who likes being in the public sphere.
"Clinton had that," he says. "Ehrlich has this joie de vivre that he gets from being in the public eye."
Ehrlich also has something Bush doesn't - his regular-guy credentials are much more valid. Bush is the son of a president whose family connections got him to those prestigious educational institutions. Ehrlich is the son of a car salesman whose football ability was the key to his education.
Schaller first encountered Ehrlich with a UMBC political science class that went to Washington and met the congressman who represented Baltimore County.
"My students just really liked the guy a lot," he says. "He's very personable, very comfortable with who he is. He's got a good sense of humor. It's hard not to like the guy on a personal level. I think that explains the disconnect between his personal approval rating and public support for his policies."
Richard Vatz, a professor in the department of mass communication and communication studies at Towson University, reports similar encounters between his students and Ehrlich.
"He has talked to my class probably 26 or 27 times in the last 13 or 14 years," Vatz says. "He's a natural. ... He's just mesmerizing in class."
Vatz, an Ehrlich backer, compares the governor's appeal to that of Ronald Reagan.
"I once wrote a piece about Reagan that talked about the rhetorical power of perceived sincerity," Vatz says. "I think that the public perceives Bob Ehrlich as an ingenuous, sincere leader. They don't think he is trying to put something over on them."
The question looming over Maryland politics is whether Ehrlich can do what Bush did - translate that personal appeal into winning a second term.
"Personal attractiveness is useful in running for office against somebody who is personally unlikable ... like Bush against Gore, or Kerry for that matter," Crenson says. "But the fact that you are personally popular does not necessarily translate into political success."
The polls underscore the problems facing Ehrlich as the 2006 election approaches.
While that approval rating looks great - much better than Bush's whose was under 50 percent - only 39 percent believed Ehrlich was doing a good job of getting things done; only 36 percent gave him positive marks for handling the budget shortfall; and a similar 37 percent said that he worked well with the legislature.
And next time, he will not be running against Kathleen Kennedy Townsend, who failed to make that personal connection with many voters. He will probably face either Baltimore Mayor Martin O'Malley or Montgomery County Executive Douglas Duncan, both men of considerable charisma.
James Gimpel, a political scientist at the University of Maryland, says that the situation reminds him of President Bill Clinton before his re-election campaign in 1996.
"He didn't really get a lot accomplished in his first term and he was quite at loggerheads with the U.S. House, which was under Republican control, yet people found him very likable," Gimpel says.
Clinton picked a very public battle with the House of Representatives which, under the leadership of Newt Gingrich, was itching for a fight. When it came to a head over a budget vote that shut down the government, Clinton came out the winner. He was able to blame the House for his lack of accomplishments.
"Candidates are sometimes able to separate themselves from the general institutions of government in the voters' minds," Gimpel says. "What Ehrlich has managed to do, and it's not that uncommon, is to exhibit to the public that he is working hard, hustling, serious, and then lay off the blame for gridlock on the legislative branch.
"This will be a central part of his campaign strategy in 2006, asking the voters to 'give me some people I can work with,'" he says.
It's not clear that will work in a heavily Democratic state that in 2002 made Ehrlich its first elected Republican governor since 1966.
For one, Ehrlich seemed to try to pick a Clinton-Gingrich-style fight with the legislature over medical malpractice, calling a special session last month, then vetoing the resulting bill because it put a tax on HMOs. That might not resonate with voters the way Clinton's stand did because it was Ehrlich's veto, not the legislature's compromise, that threatened the malpractice insurance equivalent of a government shutdown.
More importantly, many voters must feel that Ehrlich should have understood Maryland's political landscape when he came into office and adjusted to it. His refusal to compromise with the legislature could be seen as stubborn intransigence instead of admirable integrity.
"I think he's really trying to govern as though he has a Republican legislature," Walters says, suggesting that Ehrlich should take a page from the playbook of another personally popular Republican governor - Arnold Schwarzenegger.
"I think Ehrich should stop doing battle with people in the legislature," Walters says. "Instead, he should go over their heads and appeal to the people.
"That's where I think his power is. It's not in the political system, but he keeps acting as though it is there," Walters says. "He ought to take that 54 percent approval number and treat it as real, take some of the battles he has lost and go to the people with them."
Vatz contends that Ehrlich may ultimately win this battle.
"I think for a while there is going to be an apparent contradiction - but not a real contradiction - between the public not supporting Ehrlich's positions on the one hand and respecting Bob Ehrlich on the other," he says.
"Maryland has a long history of supporting liberal policies. The governor has been in office two years. For him to change the tenor of public opinion takes some time," Vatz says. "But he may well do this."