The legal case of Kevin Ring is compelling in itself.

It’s a tale of a dramatic K Street downfall, complete with an early morning FBI raid at the ex-lobbyist’s home, two trials, a conviction, $2 million in legal bills, a marriage unraveled and two young daughters whom he has tried to shield from the turmoil.

But if Ring’s recent petition to the Supreme Court is any indication, the case could also have broader implications for K Street and the entire business community. Ring argues that his honest-services-fraud conviction was based on murky definitions and relied, in part, on his legal campaign donations to members of Congress.

“I don’t think any lobbyist could survive this new standard,” Ring told me in a recent — and rare — interview. “If you’re in the influence-peddling business, you’re going to have a hard time saying you didn’t hope to have influence over official conduct.”

Almost a decade ago, Ring had a lucrative book of lobbying business and a partnership at Greenberg Traurig and had published a book called “Scalia Dissents” on the writings of Supreme Court Justice Antonin Scalia.

Now his business with the high court has become far more personal, as is his freelance work for Families Against Mandatory Minimums.

Ring is a former protégé of Jack Abramoff, the notorious ex-lobbyist who went to prison for fraud and corruption. Just weeks ago, Ring filed a petition asking the Supreme Court to hear his case. It’s a long shot, Ring acknowledged. But it’s the only thing the stay-at-home dad has left between him and a 20-month federal prison sentence.

“The case is of exceptional importance to the lobbying industry,” write Ring’s lawyers, Timothy O’Toole and Andrew Wise of Miller & Chevalier. They added that the D.C. Circuit’s “admittedly ‘subtle’ line between legal and illegal — which clearly left this jury confused — will serve as the blurry guidepost by which all Washington lobbyists are bound.”

Ring was convicted of lavishing public officials with tickets to sports games, meals at fancy restaurants and legal campaign contributions in an attempt to sway them. Ring’s filing with the Supreme Court asks the justices to consider whether a conviction of honest services fraud can occur even if there is no specific quid- pro-quo agreement — which in his case there wasn’t. It also asks whether jurors should be allowed to consider legal campaign donations when deciding whether a lobbyist engaged in corruption.

“Usually, the people I took to games, they were friends of mine,” said Ring, who was an aide to then-Rep. John T. Doolittle, R-Calif., before decamping for K Street.

Ring’s own emails during the trial proved to be damning. He revealed the transactional nature of campaign-giving and gift-giving. (Of course, lavishing aides and lawmakers with meals and gifts has since been banned as part of post-Abramoff-scandal reforms.)

Most of the characters in the Abramoff scandal, including Abramoff himself and former Rep. Bob Ney, R-Ohio, opted for guilty pleas and avoided trial.

Melanie Sloan, executive director for Citizens for Responsibility and Ethics in Washington, has tracked the Abramoff affair since its earliest stages. She said the injustice in the scandal was that so few members of Congress went to jail.

“Kevin Ring is getting what he deserved, but overall, the most powerful people escaped prosecution,” she said.

Ring, who said he cooperated with investigators for years, refused the plea he was offered because it would have required him to implicate friends and mentors, such as Doolittle.

“After telling them everything I knew, including embarrassing things and behavior I wish I wasn’t involved in, I was going to have to testify against people I didn’t think were guilty of crimes,” Ring said. “That was a non-starter.”

He refused the government’s plea arrangement. FBI agents raided his home, waking his family and spooking his oldest daughter. Shortly after, he and his wife separated.

His first trial ended in a hung jury. When a second jury found him guilty in 2011, prosecutors recommended a sentence of more than 20 years. The judge sentenced him to 20 months, but he will stay out of jail until this fall, when the Supreme Court decides whether it will hear his case. If the court declines, his sentence will kick in.

And he will have to explain to his daughters, Kiley and Audrey, ages 10 and 7, all that he and his wife, Kerrie, have sheltered them from.

“I know separating him from the girls will devastate him, but as a mother, my bigger fear is that it will destroy my girls,” Kerrie Ring wrote in 2011, pleading with Judge Ellen Huvelle for leniency during sentencing.

“There’s no getting around how awful it will be when I have to tell them,” Kevin Ring said. “But for them, I would’ve died, though, too.

“I appreciate every day with them,” he added. “You savor every single moment.”

Kate Ackley is a staff writer at CQ Roll Call who keep tabs on the influence industry.