Over the last three years of the Syrian Civil War, Hezbollah has increasingly operated as a regular army rather than in its traditional, decades-long role as a guerrilla force. The Shiite group has operated Syrian tanks and artillery, jeeps with recoilless rifles, and is even rumored to have acquired its own 75-tank armored brigade. As a result, some pundits have begun suggesting that Hezbollah has transformed into "an army in every respect," as Haaretz columnist Amos Harel has written. Others, like Foreign Policy's Nour Samaha, have suggested that "Israel may have reason to be concerned," that Hezbollah will "transfer the skills learned in Syria to any future confrontation with Israel," and fight the IDF as a conventional army.

That's unlikely. As long as the Jewish state remains the vastly superior conventional force, Hezbollah will continue to fight it according to its old successful guerilla methods. To confront the Israelis army-to-army would all but ensure Hezbollah's defeat.

Hezbollah participated in the Syrian Civil War almost from its outset in 2011, but by 2013 had transformed from its traditional insurgency tactics to acting as a counterinsurgency force against Syrian rebels. Since then, it has been conducting open warfare along established frontlines to conquer and control territory and knock out its foes, participating in combined-arms maneuvers with Iranian, Syrian, and Russian forces. Its fighters have even acted as battlefield commanders of Syrian troops.

Still, despite its growing strength and battlefield experience, Hezbollah is far from closing the gap in conventional strength with Israel. The Israel Defense Forces has made clear it intends to exploit that asymmetry "in the most muscular way possible" to score the decisive victory against the group that has eluded them in the past. The IDF's new plan, which it would follow in a war with Hezbollah, is called the Gideon Doctrine (outlined in a shorter, unclassified version titled "IDF Strategy"), which calls for a rapid deployment of ground-forces, simultaneous with aerial, naval, artillery, and cyber attacks. Israel's new strategy is to quickly penetrate Hezbollah's territory to damage its political and military infrastructure, while at the same time raining overwhelming fire on its targets.

Readily acknowledging this asymmetry in forces, equipment and capabilities, Hezbollah's leadership has said it never envisioned fighting a conventional war against the Jewish state. The group therefore has historically created its own definition of "victory"—instead of aiming to decisively defeat the IDF, Hezbollah would claim success for merely surviving and continuing to fight.

To date, Hezbollah has confronted Israel on two major occasions. The first was during Israel's occupation of south Lebanon from 1985 to 2000, when the IDF was a relatively fixed occupation force, and Hezbollah succeeded in constraining it with "rules of the game" that gave the group virtual immunity when it operated out of civilian areas in Lebanon. Accordingly, Hezbollah developed a thirteen-point guerilla doctrine designed to "defeat" the militarily superior IDF, drawing on such principles of guerilla warfare as surprise, identifying and hitting Israel's weaknesses—particularly its sensitivity to civilian and military casualties—and slipping away "like smoke" before the IDF could respond. In the 2006 Second Lebanon War, Israel no longer maintained fixed positions in south Lebanon, and the IDF was now more willing to target Hezbollah in civilian areas. Despite these changes, sensitivity to military casualties still shaped the IDF's planning. In its understandable effort to spare the lives of its soldiers, Israel did not commit ground troops in the numbers and manner necessary for victory and thus left its civilians exposed.

Hezbollah's strategy during both the 15-year occupation and the 2006 war was to force Israel to choose: imperil its home front by avoiding a ground operation, or enter Lebanon and sustain steady casualties in a drawn-out ground attrition. This was the worst nightmare of Israel's military planners, because it deprived the IDF of its main assets – mobility and striking power – while exposing the Jewish state's reluctance to suffer casualties in a protracted war. The goal of Hezbollah's strategy in both conflicts was simple: limit the timespan during which Israel could apply its full military force and, even in those moments, minimize the harm the IDF could inflict upon it, thereby denying Israel the ability to destroy the organization.

Hezbollah therefore tailored its warfare to that doctrine. It aimed to minimize the effect of Israel's air and artillery power by denying it visible targets. The group's use of small arms and light forces reduced its battlefield exposure. Hezbollah dispersed its forces into autonomous secret cells which scrupulously avoided engaging the IDF in open set-piece battles. Even its elaborate attacks on Israeli outposts during the occupation of Lebanon were short, leaving IDF artillery and helicopters to strike vainly at suspected exfiltration routes. Strategically, the group diffused its centers of gravity to deprive the IDF's standoff firepower of critical strategic assets to strike.

Target denial repeatedly proved useful for Hezbollah. During Israel's 1993 Operation Accountability and 1996 Operation Grapes of Wrath, and again throughout the 2006 war, the IDF lashed out in frustration with overwhelming air and artillery power. It wrought considerable damage upon Lebanon, and many civilians were killed. Nonetheless, Hezbollah – which continued firing rockets into Israel until the ceasefire – remained standing. To Israelis, Hezbollah's resilience made their army look ineffective.

In both conflicts, Hezbollah also constrained the IDF's use of artillery and airpower by using civilian cover, presenting the Israelis with a dilemma. Responding and causing civilian casualties made the IDF look cruel and Hezbollah more popular. It also brought international pressure on Israel to halt its operations. Israel's strike on the town of Qana on July 30, 2006, killing 28 civilians including 16 children, is acknowledged even by Israeli leaders as the point at which the Second Lebanon War turned in Hezbollah's favor. The previously sympathetic international community (including the United States) began pressuring Jerusalem to accept a disadvantageous ceasefire, as Hezbollah continued firing Katyushas.

But Israel could not grant Hezbollah immunity to operate against it from civilian areas. Instead, the IDF sent in ground troops to root it out. But this is exactly how Hezbollah wanted to confront the Israelis—as exposed foot soldiers on its level, without aerial or artillery cover—and exploit their relative casualty sensitivity. During the south Lebanon conflict, Hezbollah bled the IDF's patrols with roadside bombs and lethal ambushes that gradually wore down the Israelis. In 2006, Hezbollah opted to bog down its enemy's numerically and qualitatively superior troops in brutal urban combat.

In purely military terms, the reality on the ground—and the body count—was always in Israel's favor. However, Hezbollah grasped early on that perception was often nearly as important. Contrary to its martyrdom-seeking image, its operations were not suicidal and were carried out only when success was relatively certain. Hezbollah also masterfully used the media to give the impression that it was making real gains against the IDF, obviating the conventional military need either to conquer territory or decisively defeat their foe.

In 1994, Hezbollah released a film of its guerillas storming the IDF's Pumpkin Outpost in south Lebanon, firing at its defenders and planting their flag before the video abruptly cut. Though Hezbollah's propaganda claimed it had captured the hill and "purified it of the Zionists," the garrison's defenders repulsed the attack with only one fatality. However, this relatively minor incident was perceived as a major military defeat in Israel, with some analysts going so far as to declare that the army's "fighting spirit has been broken."

In the Second Lebanon War, Hezbollah repeated this psychological success, as when Nasrallah gave a perfectly timed "play-by-play" of the group's July 14, 2006 strike on the INS Hanit. He told his listeners—both Lebanese and Israeli—that the ship would sink with its sailors aboard. In fact, four crewmembers were killed but the ship didn't sink. But the psychological victory was complete, turning much of Lebanese public opinion in favor of the war, and demoralizing Israel.

Hezbollah survived both conflicts by using Lebanese civilian and IDF casualties to erode international and domestic Israeli support for those wars. By denying the IDF any progress on the ground—and in 2006 by firing hundreds of rockets at the Galilee until the ceasefire—it created a perception of Israeli defeat.

As a regular army, Hezbollah would be abandoning these guerilla warfare advantages, most importantly its conception of victory, without compensating with conventional strength that challenges Israel's. The battlefield results Hezbollah achieved against irregular militias in Syria cannot be replicated in the next war with the IDF. The group simply lacks the manpower, budget or military assets to match the IDF, either quantitatively or qualitatively.

Even though Nasrallah has threatened to conquer the Galilee, it would likely be another Hezbollah theatrical performance—a photo opportunity for its fighters to briefly enter Israeli territory and plant their flag. Anything beyond that would end in dismal failure. Hezbollah would also be sacrificing its operational secrecy and opacity, exposing itself to the IDF. Israel could then more easily and quickly decimate the group's fixed locations and forces and cut its supply and communication lines with standoff firepower – assets which Hezbollah lacks and to which it does not have effective countermeasures.

In fact, Hezbollah's preparations indicate it intends to fight another guerilla war with Israel. The group has expanded and upgraded its already vast tunnel network. Once again using civilian cover, it has built up over 200 Shiite villages in South Lebanon into fortified fighting zones, with rockets, anti-aircraft missiles, and command centers. Israel will again be left to choose from the unsavory options of striking the villages and killing civilians, or withholding fire. Despite rhetoric from the IDF brass that these areas will be considered targetable military bases, the Gideon Doctrine still acknowledges this as a real dilemma.

Additionally, though Hezbollah's rocket arsenal has grown to 150,000 rockets, the majority are inaccurate and relatively ineffective Katyushas. Hezbollah's emphasis on Katyushas is its answer to the sophisticated multi-layer missile defense system Israel began developing in 2007, and which is now nearly fully operational. With Hezbollah expected to fire a daily average of 1,500 rockets in the next war, the cost for Israel of relying exclusively on missile interceptors would be prohibitive. Moreover, Israel's defensive systems will not be able to intercept them all. Hundreds will likely still strike the north, causing the similar disruption to civilian life and the economy, and demoralizing the Israeli home front, as in the 2006 war. To halt the strikes, Israel will again be forced to send its troops into Hezbollah-controlled villages, where the group possesses the defender's advantage.

Hezbollah wants the next war to remain short. But Israel excels at short, sharp and decisive operations, a traditional preference honed by the Gideon Doctrine. Within that short time, Hezbollah will need to remain elusive to deny Israel the ability to drive home its full military advantage—and thus survive and claim victory. The Party of God can only do so as a guerilla force. When fighting Israel, Hezbollah's Syrian battlefield strategy becomes its disadvantage. Although it has gained valuable experience in the Syrian war, those lessons will be of little use in facing its traditional enemy south of the border. During the next war, Hezbollah is well aware of one simple fact: Israel is not Syria.

David Daoud is an Arabic-language research analyst at the Foundation for Defense of Democracies.