In Massachusetts, where his friend and political ally Deval Patrick won the top office by campaigning in an eerily similar fashion to Senator Obama, voters have a Petri dish to examine what the Democratic candidate’s presidency might be like should he win in November.

Comparisons between the two men are in order once again. Mr. Obama celebrated his 47th birthday in Boston last night at a $4 million fundraiser with Governor Patrick at his side.

Like Mr. Obama’s campaign, Mr. Patrick’s was heavy on sweeping rhetoric and increased expectations. Advised by, among others, David Axelrod, who is also Mr. Obama’s chief strategist, Mr. Patrick offered state voters the prospect of great change.

In the first months of his governorship, Mr. Patrick weathered his worst political problems. After several months, he stabilized his position by bringing in an experienced team of staffers. Yet the extraordinary promise his campaign once offered has given way to ordinary political wrangling. For example, to help pay for his ideas, Mr. Patrick turned to backing the introduction of legalized casino gambling in Massachusetts. When it looked like the legislature would defeat the gambling effort — which it did — Mr. Patrick quietly headed out of state and scored a book deal in New York.

For Mr. Patrick’s ambitious agenda, which includes all-day kindergarten, to succeed, the state needs revenue. As a relative newcomer to the State House, where the business of state government takes place, Mr. Patrick has been unafraid to criticize programs that have been political sacred cows. The best example is that of paying police to do work that can be done by civilians at a cost to government of an estimated $100 million a year.

Massachusetts, unlike the other 49 states in America, requires the presence of uniformed police at roadway construction sites. In March, Mr. Patrick appeared at a press conference with other state leaders to voice his intention to revise this policy. In the face of sharp opposition from police and public safety unions, the plan seems to have lost steam, but is not dead.

When faced with a battle against legislators, the governor also acquiesced to the legislature in agreeing to a $10-a-month cost of living increase for state pensioners. He is expected to sign legislation that could cost the state millions over the long run when most current officials are out of office.

The president of a state fiscal watchdog, the Massachusetts Taxpayers Association, Michael Widmer, says the spending on public employees is not sustainable. Mr. Widmer calls police details “probably the most important symbolic issue as it relates to public dismay with public spending.”

Another area in which Mr. Patrick will expend political capital is education. Not a proponent of charter schools, Mr. Patrick has unveiled what he is calling “readiness schools.” Like charter schools, these institutions would operate outside of the usual public school teacher contracts; unlike them, they would answer to local school committees, not the state. The author of “The Bluest State” and a WBZ-TV political analyst, Jonathan Keller, cautions that the “readiness schools” are “an anti-charter school tactic.”

Mr. Patrick’s greatest successes are in areas where there is support from the legislature. Since taking office Mr. Patrick has been a vocal proponent of Massachusetts becoming a national and international center of biotech research. He pushed for the passage of a $1 billion life sciences initiative and was named “Governor of the Year” by the Biotechnology Industry Organization.

His courageous decision to campaign on behalf of a controversial wind farm off the coast of Cape Cod, Cape Wind (even when it was opposed by Senator Kennedy), has looked better with energy costs spiraling upward.

Mr. Patrick believes he can grow jobs in Massachusetts by making the state a haven for clean jobs. The governor signed his Clean Energy Bill last month, which, among other provisions, ties utility contracts to the funding of local clean energy companies.

Mr. Patrick’s first two years have shown how hard it is to make change happen, an indicator of what things might be like for Mr. Obama.

In addition to a common political consultant, Mr. Axelrod, Messrs. Patrick and Obama share aspects of their biography; they are black, youthful men who graduated from Harvard Law School. Mr. Obama is a resident of Chicago; Mr. Patrick is Chicago-born. Mr. Patrick, despite having served as the head of the civil rights division in the Department of Justice, had minimal exposure to state government before he was elected as governor.

Likewise, Mr. Obama has been in federal office since 2005 and never as an executive; the bulk of Mr. Obama’s experience has been as a community organizer and a senator on the state and federal levels.

Given their similarities, Mr. Obama is likely to find negotiating with the House and Senate leadership, both of whom are from his own party, to be tougher than addressing thousands of enthusiastic Europeans.

It’s easy to imagine an Obama administration that is rocky at the beginning but then settles into the conventional, sometimes grinding, pattern of governing. “The question I have about both of these guys is what do they really want to do?” asks Mr. Keller. “Is it about proving the point by winning the campaign, getting the power, and then engaging in navel gazing and self-adulation or do they really want to change the facts on the ground?”

Mr. Gitell (gitell.com) is a contributing editor of The New York Sun.