VietJoy

That's an assessment shared by current and former U.S. officials. 

"We have killed one of the most significant militant actors inside the Iranian government," said Patrick Kimmitt, a former U.S. assistant secretary of state for political-military affairs. "It takes the whole issue of the United States and Iran, and the United States and Iraq to a whole new place. This is an inflection point that can't be understated."

"He was the major figure who ran Iran's growing regional ‘Islamic Resistance' network that has tens of thousands of fighters from Palestinian areas, Lebanon, Iraq, Bahrain, Syria," tweeted Phillip Smyth, an analyst at the Washington Institute for Near East Policy, a U.S.-based think tank. 

"The consequences of killing Soleimani are hard to grasp; this is the biggest news in the Middle East for years," says Charles Lister, author the book "The Syrian Jihad." He says his slaying "far eclipses the deaths of [al-Qaida leader Osama] Bin Laden or [Islamic State leader Abu Bakr al-] Baghdadi in terms of strategic significance and implications. The U.S. and Iran have been engaged in a dangerous tit-for-tat for months now, but this is a massive walk-up the escalation ladder. Israel has repeatedly spurned the opportunity to kill Soleimani for fear of the consequences of taking out Iran's most powerful operative in the world, someone who's power is outshone only by Iran's Supreme Leader. His death is a serious loss for Iran's regional agenda."

In Iran and among its Shi'ite allies across the Middle East, Soleimani had near-mythical status, and he was included in Time magazine's 100 most influential people, listed as a cross between "James Bond, Erwin Rommel and Lady Gaga."

His celebrity status in the Middle East was a far cry from his humble start in the tiny village of Qanat-e Malek in southern Iran's Kerman Province to an impoverished peasant family. As a teenager, he moved to the city of Kerman to get work as a construction worker, remitting most of his earnings back to his parents. He later became a water contractor. 

He was a fan of martial arts and a karate black belt. Aside from that, his other great passion was religion. He fell into the circle of a protege of of Ayatollah Khomeini, which allowed him to join and rise up the ranks of the Islamic Revolutionary Guard Corps, which was set up after the 1979 revolution to protect the new Islamic regime. As a guardsman he participated in the suppression of a Kurdish uprising in West Azerbaijan Province. 

He later rose to fame as a daring field commander in the Iran-Iraq War. In his New Yorker profile of Soleimani, Dexter Filkins quotes the general saying: "I entered the war on a 15-day mission, and ended up staying until the end." Soleimani added: "We were all young and wanted to serve the revolution." He ended up as a divisional commander, often leading commando raids deep into Iraqi territory and was seriously injured in one attack.

In the 1990s, Soleimani was given command of the elite al-Quds force, a shadowy unit that undertakes missions outside Iranian borders, often working with its client in Lebanon, the Shi'ite militia Hezbollah, which al-Quds helped to establish. In that role Soleimani became the architect of Iran's expansionist Mideast strategy, shaping a "Shia crescent" across Iraq, Syria and Lebanon. 

In a broadcast interview in October, Soleimani disclosed he'd been in Lebanon in 2006 helping to direct Hezbollah's battles with Israel. His irregular warfare background proved crucial for Iran in Iraq, say former U.S. intelligence and military officials. He was one of the tacticians behind Iraqi Shi'ite attacks on Western soldiers after the 2003 U.S.-led invasion of Saddam Hussein's Iraq,

"We have been in a proxy war with Iran's revolutionary guards for 10 years, longer than 10 years. Qassem Soleimani and his people were killing Americans in 2005 and 2006," said former U.S. official Patrick Kimmitt. He says the Quds Force supplied Iraqi Shi'ites with the most deadly improvised explosive devices the Americans saw in Iraq. Scores of Americans were killed by them. 

War makes for strange bedfellows — American military commanders had little choice in 2014 but to coordinate airstrikes with Tehran-sponsored Shi'ite militias in Iraq against their common foe during the fightback against the Islamic State terror group. In the wake, though, of liberating Mosul and other Iraqi towns of IS, that temporary alliance of necessity fell apart. Soleimani had been a frequent visitor to Baghdad in recent weeks, say analysts, helping to direct Shi'ite attacks on U.S. forces in Iraq and the protests aimed at expanding Iran's influence on Iraq.  

Soleimani stepped out of the shadows in recent years, emerging as one of the masterminds of the military comeback in Syria by Iranian ally President Bashar al-Assad. He coordinated airstrikes with Russian generals, frequently traveling to Moscow, and analysts say he was key in smoothing out the battlefield efforts of Assad's regular forces with Shi'ite militias, which Iran helped to raise from Afghanistan and Iraq. Soleimani appeared in press photographs and broadcasts visiting the front lines — and even appeared in a popular Iranian music video. 

Last year, Soleimani warned the U.S. president in a boastful video message: "I'm telling you Mr. Trump the gambler, I'm telling you, know that we are close to you in that place you don't think we are. You will start the war but we will end it." 

The threat was in keeping with his bragging in 2010 to U.S. General David Petraeus, who was then the commander of U.S. forces in Iraq. The two were in communication and Petraeus disclosed that the Iranian general had told him in one message: "You should know that I, Qassem Soleimani, control the policy for Iran with respect to Iraq, Lebanon, Gaza and Afghanistan."

Soleimani is likely to prove a challenging foe in death, too, according to analysts and current and former Western officials. Some are critical of the targeted killing of the Iranian, saying that U.S. President Donald Trump's predecessors in the White House passed targeting Soleimani, fearing messy, violent repercussions. 

Analyst Charles Lister says in the wake of Soleimani's death, the U.S. will face serious challenges in both Syria and Iraq — with Iran eager to retaliate. "The U.S. presence in Syria now looks very vulnerable, having already shrunk in size and weakened in terms of credibility and partner trust. A single attack on U.S. positions could feasibly catalyze a military withdrawal and second abandonment of the Kurds. In Iraq, U.S. diplomatic and military facilities are almost certain to come under some form of attack and covert intimidation," he says.

But in Iraq, Lister notes, the reaction likely will be complex and could spur anti-Iranian Sunni activists. "Weeks of protests across Iraq have shown the popular tide swaying against Iran and these newly tense circumstances could feasibly provide an environment for Iranian proxies to be perceived as the source of more problems than solutions," he says. 

Other analysts say the U.S. move will send a clear intimidating message to Tehran that no one in in the Iranian regime is safe. "For all the talk about a full upscale war between Iran and the U.S. over the killing of Tehran's terror master Qassem Soleimani, the fact that Iran now realizes America is not a paper tiger anymore will resonate in the ears of Supreme Leader Khameini," says counterterrorism analyst Olivier Guitta, who runs GlobalStrat, a London-based risk consultancy.

He adds: "Despite all the declarations of vengeance from the Iran regime and the likelihood of attacks abroad against U.S. and Israeli interests, the mullah's regime would like more than anything to save their skins and can't afford a full-blown conflict with the U.S."