This Bastille Day, rather than storming the prison, U.S. District Judge Ronald L. Buckwalter will determine how long former political pooh-bah Vincent J. Fumo ends up serving in one.

After all these years of Vince's being the Prince of the City and Harrisburg, of battling and fighting for you, but often for himself, in that $9-for-you, $1-for-him way of his, it comes down to this: He's between a rock and hard time.

Talking to a battery of leading defense lawyers and former prosecutors, I can tell you this: Based on the sentences of other corrupt officials, Fumo's most likely going away for a long time, and soon.

Convicted in March on all 137 counts, the former state senator faces a possible term of 21 to 27 years. But federal sentencing guidelines are just that, no longer mandatory, and thus up to the judge's discretion.

Prison is punishment. But it's also used as a deterrent to public officials who might be tempted to view their position as lord and master, a district as empire, staff as serfs, taxpayers as knaves.

Justice may take some time, decades in this case, but the sentence says: Behave like this and you, too, will ultimately end up behind bars.

Fumo is 66. His questionable behavior dates to the Nixon era, when he was forced to resign from a state job for allegedly spying on potential political rivals of Gov. Milton J. Shapp.

With federal sentencing guidelines, the amount of money matters ($4 million), as does the size of the conspiracy (a gang of five or more), serving as the leader (indubitably), and violating public trust (slam-dunk).

Sitting in the courtroom July 14 will also be the Ghosts of Defendants Past: former City Councilman Rick Mariano, former City Treasurer Corey Kemp, and former Independence Seaport Museum president John S. Carter.

Prior sentencing should provide a road map. Mariano received 61/2 years for taking $23,000 in bribes (and $5,400 in fees for, from the looks of it, a rarely visited gym). In the pay-to-play scandal, Kemp was led away from court in manacles, sentenced to 10 years for gifts of $10,000, a new deck, and an all-inclusive trip to the Super Bowl, and the Eagles weren't even playing.

"If this was a baseball team, Corey Kemp would be a bat boy," L. George Parry said at his client's sentencing. With Fumo, Parry says, today "there's a clarity of the awfulness, and a real need for punishment."

Two years ago, Carter was locked away for 15 years for taking $1.5 million. That may become the benchmark, defense attorneys and former prosecutors say. How can Buckwalter send Fumo away for less than that?

Obstruction, as Watergate showed, is also key to sentencing. "It's just a very blatant offensive fraud that makes it worse than the ordinary person who takes money from his employer," says Penn law professor Stephanos Bibas, an expert on sentencing guidelines. "This is a breach of public trust."

The defense, now led by D.C. litigator and federal sentencing authority Sam Buffone, is allowed to cite Fumo's good deeds. It can call witnesses - though it would be advisable not to ask the governor, who didn't help Fumo's cause during the trial. Fumo may speak on his own behalf, though that may not help either, given his flashes of "all I had to do was show up and vote" arrogance.

Prosecutors will no doubt argue that Fumo "shamelessly perjured himself dozens of time," as they assert in a court document filed last week. This could increase the sentence. The government will seek restitution of close to $4 million.

"The issue here isn't what the harm was to society. The real issue with Fumo is how he diminished people's respect for government," says Pepper Hamilton's Gregory Paw, a former prosecutor in Philadelphia and New Jersey who helped convict former Newark, N.J., Mayor Sharpe James. "The fact that this is a pattern of conduct over a period of time, the judge has to think about the message he's sending to the community with the sentence."

Fumo was a tough legislator with a delicate constitution. His heart problems are as old as his trial in 1978, where he was charged with assisting in adding 33 ghost employees to the payroll of Senate predecessor Buddy Cianfrani. The jury conviction was set aside by a judge three years later.

Fumo suffered a heart attack in March 2008, and collapsed on the floor of the state Senate last June. During the trial in January, he became dizzy, nauseated, and exited the federal court building by gurney. If health is determined a factor, he can be sent to a federal medical prison facility. There's even one in Minnesota, close to the vaunted Mayo Clinic.

"When a defendant is about to be sentenced to jail, no one is ever in good health," says former Assistant U.S. Attorney Barry Gross, now a partner at Drinker Biddle. "The other guarantee is, once he gets sentenced, he'll see God."

The judge has three choices upon sentencing: He can have Fumo locked up immediately, allow him to self-surrender in a month or so, or set him free on bail pending appeal, a process that could take two years.

There's little question what prosecutors prefer. "Justice delayed is simply justice denied," they wrote in the recent court filing.

Fumo isn't called Prince for nothing, living as he does in a 27-room mansion, with two homes at the Shore. Buckwalter's unlikely to allow Fumo to live as he does for two more years, many lawyers believe. Most likely, they say, within a few months Fumo will truly live, as he always believed he should, on the largesse of Other People's Money.

Contact staff writer Karen Heller at 215-854-2586 or kheller@phillynews.com.