Lebanon is basking in the high summer of what promises to be its best tourism season ever. Since the peaceful re-election of its pro-Western government in June, Lebanon has been flooded with visitors — mostly expatriate Lebanese and wealthy Gulf Arabs. Last month alone, the country of 4 million welcomed more than 1 million tourists. But while hotels are booked out and the nightclubs packed with revelers, rumors of war are never far away.Israel and Hizballah have been issuing threats since the weekend, when an Israeli official made the improbable claim that the Lebanese Shi'ite militant group was behind an alleged al-Qaeda plot to kill Israel's ambassador to Egypt — and other attempted operations against Israelis abroad. (Hizballah and al-Qaeda are not allies, and al-Qaeda leaders have publicly criticized the Lebanese organization — and are believed to have backed rival Sunni militia in Lebanon.)"If one hair falls off an Israeli's head, we will hold Hizballah responsible," said Deputy Foreign Minister Danny Ayalon. Then, on Tuesday, Israeli Prime Minister Benjamin Netanyahu upped the ante, promising to hold all of Lebanon responsible for any provocation by Hizballah. Hizballah responded by vowing that the next war would be even bloodier for Israel than the 2006 clash that killed about 160 Israelis and about 1,200 Lebanese.Despite the saber-rattling, analysts on both sides of the border believe war is unlikely to break out, at least for now. Hizballah would risk alienating its own support base — and the rest of a country that hasn't yet repaired all the damage from 2006 — by provoking another war. And Israel is unlikely to scupper the Obama Administration's push for a comprehensive Middle East peace by launching a war of choice. But the war of words is a reminder of an ever-present danger of military adventurism across the Israel-Lebanon border. And the danger is amplified by the fact that Israel sees a potential conflict with Hizballah as another front in its showdown with the movement's key sponsor, Iran. Still, the track record of cross-border military operations against guerrilla enemies should give Israel pause for thought.Israel's first Lebanon debacle began in 1978, when then Defense Minister Ariel Sharon used the pretext of preventing attacks by Palestinian militants in the southern part of the country for an invasion that went all the way to Beirut, in the hope of installing an Israel-friendly government of Lebanese Christians. The operation was a spectacular failure, with the assassination of Israel's chosen man, Lebanese President-elect Bashir Gemayel, and his supporters' reprisal massacres in the Palestinian refugee camps at Sabra and Chatila that still haunt the Israeli psyche. The Israelis did drive the PLO out of Lebanon, but their invasion and occupation caused Lebanese Shi'ites backed by Iran to form Hizballah — an enemy far more dangerous to Israel than the PLO ever was.Israel remained in Lebanon for 22 years, and then, six years later, it invaded again — in response to a 2006 Hizballah cross-border attack on a squad of Israeli soldiers. This time, Israel — encouraged by the Bush Administration — sought to eliminate Hizballah as a military threat. Instead, the most powerful army in the Middle East found itself pinned down in the hills of southern Lebanon by small bands of guerillas armed with high-tech anti-tank weapons, while one of the world's best-equipped air forces failed to suppress rocket fire into northern Israel. An official Israeli inquiry lambasted the government for launching a war without clear and achievable goals. Still, Israel arguably repeated the mistake at the end of last year by launching a major offensive against Hamas in Gaza, with the goal of eliminating the military threat from Hamas — which it never did.The net effect of Israel's military campaigns against Hamas and Hizballah has been to leave those groups politically strengthened, while the massive collateral damage inflicted on Lebanon and Gaza has turned world opinion against Israel. Hizballah has re-armed and the Israelis themselves warn that it is stronger than ever militarily. And the Shi'ite movement is politically more powerful in Lebanon than it was in 2006. Recent reports indicate that Hizballah may have as many as 40,000 rockets aimed at Israel, is trying to increase its anti-aircraft capability, and may have missile technology that would enable it to strike Tel Aviv.Still, Israel's leaders believe they have no choice but to plan for further military action, because they have concluded that the Arab and Muslim world will never truly accept Israel's existence, and that withdrawing from territory (as Israel did from Lebanon in 2000 and Gaza in 2005) only brings more rocket fire. For all the hand-wringing after the embarrassment of the Second Lebanon War, Israel's military still prides itself on the fact that the Lebanese border has been surprisingly quiet since 2006, and that Hamas is not suppressing rocket fire from Gaza. Military force, at least as a deterrent, appears to be working.Rather than placing its hopes in settling its conflicts with Arab neighbors by moving toward withdrawing from the West Bank and the Syrian Golan Heights, Prime Minister Benjamin Netanyahu's government is building a case for a military strike against Iran. Israeli officials believe that Tehran's support for Hamas and Hizballah, and its looming capacity to build a nuclear weapon, make tackling Iran their overriding priority.The problem, of course, is that history suggests that whatever damage Israel may succeed in inflicting on Iran's nuclear facilities will likely come at a cost of a hardening of political sentiment against the Jewish state. Iran may be able to rebuild its nuclear program more quickly than Israel would be able to reverse the trend that has already given the next generation in Lebanon and Gaza a burning desire for revenge.