Former Israeli Prime Minister Ehud Olmert.

Like a supremely confident acrobat, former Israeli  Prime Minister Ehud Olmert has had an unusual 40-year-plus career walking the narrow ledge between what is legal and what is illegal, showing that politics demands a huge ego, but also that big egos can lead to a great fall.

“The former prime minister has had to face at least eight cases where he was suspected of criminality,” observed Israel TV Channel Two in a legal commentary released after Olmert’s conviction on bribery charges Monday.

But Ehud Olmert, from the time he entered the Knesset at age 29,  was never afraid of the risks.

As Professor Harold Lasswell wrote many years ago, the “political man” or “political personality” wants to sway people with oratory or believes that he or she is specially suited to get things done. A big ego is needed for big tasks, and a healthy ego can withstand criticism from rivals and the media that would crush lesser egos.

However, a big ego can turn into arrogance that leads some politicians to take huge personal or national risks, to ignore criticism or restraining advice, and even to believe they are invincible, unstoppable.

“I did it because I could,” ex-President Bill Clinton once said when asked about why he continued with his dangerous affair with Monica Lewinsky.

France’s president Francois Hollande similarly carried on a dangerous extramarital affair, bicycling to trysts with his lover, confident  he would not be caught.

Similar sentiments were certainly evident in the conduct of other convicted Israeli politicians—like Moshe Katsav or Haim Ramon—who believed that no one would dare spurn their sexual advances, let alone file complaints against them. But a sense of invincibility extends beyond the sexual/political arena.

Political success and adulation feed the ego, causing   politicians to believe they can overcome all obstacles, even break the law with impunity. This tendency gets worse when a politician has a brush with defeat or political oblivion.

Richard Nixon returned from two electoral defeats—in 1960 to John Kennedy, and in 1962 for governor of California—to become the president of the United States. He translated this success as a license to abuse his powers at several levels. The result was Watergate.

Ehud Olmert came from the fringes of Israeli politics to become prime minister. He unseated his own father, Mordechai, to take his place in the tiny Free Center Party that eventually became part of Likud.

Later, when Olmert  was pushed from the national spotlight and dropped to a low rank inside Likud, he moved to a local playing field and became mayor of Jerusalem for two terms, showing oratorical abilities—and not from notes or a teleprompter. Olmert was one of the finest extemporaneous speakers on the political scene.

Anyone who challenged Olmert found that he was a masterful verbal puncher who could jab and slug in almost any situation, but there was almost always a haunting undertone to Olmert’s career—the buzz of accusations and rumors of wrong-doing.

At least four times Olmert  faced serious criminal trials in a career that spans more than 30 years. In 1996, he was indicted with helping the Likud to “cook the books” in the 1988 elections. Olmert, the Likud treasurer, said he did not know what his co-defendants were doing.

The judge gave him the benefit of the doubt, and Olmert barely got acquitted along with a stern rebuke, while co-defendants were convicted and did jail time.

It was a similar story in the Bank of North America trial, when it was shown that Olmert had gotten a $50,000 loan in 1981 from Yehoshua Halperin, the head of the bank, for whom he did favors. Olmert did not repay the loan, but he narrowly escaped conviction, while Halperin went to jail.

Olmert acted in similar fashion with other loans, other gifts and benefits that he received from other wealthy patrons. He did not repay. Sometimes, after being questioned, he repaid at a cut-rate after many years, even decades.

The former prime minister was charged with getting a beautiful house in the German Colony in Jerusalem from businessman S. Daniel Abraham, the developer of the Slim-Fast diet food.

Later, Israel’s Inspector-General charged that Olmert had acted on Abraham’s behalf in a bank deal, and he recommended that Olmert be prosecuted, but authorities declined to bring charges for a variety of technical reasons such as statute of limitations or lack of clear-cut proof.

Olmert used this narrow legal/technical escape several times, but each time, he seemed to be getting closer to disaster. In 2012, he faced three sets of criminal charges involving among other things getting cash-filled envelopes from businessman Morris Talansky, rigging political appointments and double-billing clients for trips.

A three-judge Jerusalem court convicted Olmert on relatively minor charges, but gave him a suspended sentence, accepting, by reason of doubt, Olmert’s contention that he thought the cash was a political contribution and not a bribe and that he really did not know about the double-billing.

Olmert and his backers took the suspended sentence as a huge victory, even discussing the possibility of Olmert again running for prime minister, attacking the State’s Attorney and the Inspector General for “hounding” Olmert. They became very arrogant and a little careless.

“If I were the State’s Attorney I would not just resign, I would commit suicide,” asserted journalist Amnon Dankner, a close Olmert friend (who recently died). Olmert and his attorneys also haughtily insulted the prosecution, charging them with “polluting the legal process.”

Israeli prosecutors are appealing the light sentence and the overall partial acquittal ruling to Israel’s Supreme Court, and there are signs the case may be re-opened.

Another reason the case may be re-opened is that Olmert’s co-defendant and secretary of 30 years, Shula Zaken, has given police new proof of Olmert’s alleged wrong-doing, including a tape where Olmert asks Zaken not to testify against him.

“If you testify, I will never be prime minister again,” says Olmert on the tape that was aired on Israel Radio just before a gag order went into effect.

Ms. Zaken was convicted Monday with Olmert. She will do serious jail time, but she will try to make a deal in return for information. Her ego and Olmert’s were also a factor in her eleventh-hour decision.

Zaken was offended by the haughty tone of Olmert and his lawyers. They took her lightly, and she will make them pay heavily.  Zaken was Olmert’s gate-keeper for years, and she is likely to become the one who buries his career.

At age 68, the acrobatic and athletic Olmert may find that he is closer to being behind bars and wires than climbing the political high wire again.

Dr. Michael Widlanski is the author of Battle for Our Minds: Western Elites and the Terror Threat, published by Threshold/ Simon and Schuster. He teaches at Bar-Ilan University, was strategic affairs advisor in Israel’s Ministry of Public Security, and is the Schusterman visiting professor at Universityof California, Irvine for 2013-14.