When former Gov. John G. Rowland was sentenced to a year in prison Friday, it underscored a sobering fact for Connecticut politicians: Federal law enforcement authorities are carting them off to penitentiaries at an unparalleled rate.

``I have said before that if things keep going the way they have been in Connecticut, you're going to run out of mayors,'' said Chris Swecker, deputy director of the FBI's criminal division.

And not just mayors.

Over a decade and a half, federal agents have convicted, among others, a state treasurer, a candidate for secretary of the state, three big city mayors, a state judge, bureaucrats, inspectors and dozens of their political colleagues, not to mention the bankers, financiers, fund-raisers and construction executives and criminals who pay them off. Add to that a guilty plea by the ex-governor, the conviction of his deputy chief of staff and the indictments of three other gubernatorial associates and a record emerges that gives lie to the picture of Connecticut as a seat of Yankee propriety.

``They have had incredible success,'' Austin J. McGuigan, a former chief state prosecutor, said of the federal law enforcement record on government corruption in Connecticut. ``I don't know where else in the country this record is equaled. It is a stellar record.''

Stellar, perhaps. But for reasons that are clear to no one, it has not been as sobering as it could be to Connecticut's political class. Even though barrels of ink have been drained on scandal coverage, federal investigators continue to have little difficulty uncovering sleaze. Federal agents in Connecticut routinely take aim at new groups of politicians almost before the prison gates have closed on the previous targets.

Federal prosecutors, along with FBI and IRS agents, are running multiple corruption investigations -- a significant personnel allocation in a tiny jurisdiction such as Connecticut. Investigations are known to be underway in Bridgeport and Waterbury -- at least the second time around for each city since the late 1980s.

The serial scandals beg questions about which came first: Are the state's federal law enforcers particularly adept at rooting out political miscreants? Or is the state's political culture thoroughly corrupt?

There is some truth in both propositions, according to legal and political experts.

Officials at FBI headquarters in Washington attribute the string of convictions, not surprisingly, to a particularly talented local cadre of investigators and prosecutors working closely with the bureau's Connecticut division, run by Special Agent Michael Wolf.

``Mike Wolf has probably the most effective public corruption program in the country,'' said Swecker, who directs all FBI crime fighting programs. ``The New Haven office has been the leading office in the country.''

There also is agreement that the political culture in Connecticut -- a state where a former Rowland aide buried ill-gotten gold coins in his backyard -- is riddled with greed and a corrupt sense of entitlement.

``Statistically, I would say it's true,'' said retired Connecticut FBI agent Michael Clark, who supervised or worked on, among other things, investigations of Rowland, former state Treasurer Paul Silvester, two Waterbury mayors, a Superior Court judge and a city manager in Meriden. ``By the number of cases being generated, something is going on. There is no question about that. We have just had an endless supply of targets. It doesn't stop.''

While no one disputes the numbers, not everyone thinks the long and expensive prosecutions behind them are justified. Attorney Hugh Keefe, who has defended accused mayors in Danbury and Waterbury and is representing an indicted former Rowland aide, believes federal authorities have established a threshold for investigation that is too low. He believes federal authorities are prosecuting trivial political crimes in Connecticut that are ignored elsewhere.

``I believe, and I don't think I'm far off the mark, that what has happened in Connecticut happens everywhere and has happened since the first vote was cast in this country,'' Keefe said. ``Maybe the public's intolerance has increased. I don't know. One of the side effects of all this, besides really detracting from the image of the state of Connecticut, is to discourage good people from getting involved in politics.

``I think there is such a thing as setting the bar too low, where every single thing is looked at suspiciously as an indictable offense. When I look at the Rowland case very closely, I wonder, what did this guy do? The image got out of control and the public was convinced he was corrupt. But when you look closely at what he did, it was nickels and dimes. And I've known a lot of politicians, who I can talk about now because they're dead, and what was going on in the Rowland administration is really not out of line with what I know was going on in the '50s, '60s, '70s.''

The current run of federal corruption convictions dates to the appointment in 1985 of U.S. Attorney Stanley A. Twardy Jr. Ambitious and politically seasoned, Twardy assumed office looking for a way to distinguish his tenure as the state's top federal prosecutor. What he saw was a lack of interest in prosecuting corruption.

``I remember discussing that with Stan at the time,'' said a colleague who has since been appointed to a judgeship, and who spoke on condition of anonymity. ``There was no other game in town.''

There had been another game in the late 1970s and early '80s. McGuigan, then the state's chief prosecutor, made aggressive use of the investigative one-man grand jury, initiating more than 20 such probes during his tenure. Many of those were directed at allegations that influential politicians were collecting political payoffs from businessmen hoping to win state contracts. It was a prescient investigative premise, as subsequent federal investigations would prove.