Which heads of state and high ranking officials are you referring to?
Leaders in Lebanon, Pakistan, India, for example; former Soviet or Russian leaders... .
Which of these leaders were taken out by professional assassins recently? You might be confusing "professional" assassins, with fanatical religious terrorist types.
I would note the recent assassination of Bhutto was hardly a hit by a professional assassin, due to the fact a "professional" in that sense, would not have blown himself up along with many others creating a very messy scene in the process. Looking at the scene images, you can see one individual pointing a handgun. A handgun would not be the weapon of choice for a professional assassin. I would guess Bhutto was killed by extremist, terrorist, religious fanatics etc, not what one would consider a "professional" assassin.
The term "professional" would seem to suggest someone who is highly skilled, makes a very detailed plans, and surgically executes that plan with precision and gets away with it.
Incidents like Hinckley and Reagan are aberrations
Actually they're typical.
Modern notable assassins/attempted assassinations in the U.S. would include Reagan, JFK, Wallace, Martin Luther King, John Lennon, Robert Kennedy etc...None of which were killed by what one would consider "professional" assassins.
Even going way back to Lincoln, the assassin was hardly a professional.
You must be kidding me. Bhutto’s assassination was set up by Paki Intelligence, using shills. JFK was NOT killed by Lee Harvey Oswald (and if you believe the Warren Commission I have a bridge in Brooklyn to sell you); the JFK hit was a professional action. The Lebanese PM was taken out by Syrian Intelligence. The Mossad regularly takes out high-profile targets; so did the KGB. Pope John Paul II’s would-be assassin was working for Bulgarian Intelligence.
Sure there are random nuts who once in a while try to kill someone powerful or famous. But the serious hits are almost always done by professionals.