The Israeli government delayed air strikes against Hizbollah, the Lebanese guerrilla movement, for so long because it has more to lose than gain by escalating the war in Lebanon. By yesterday morning it could wait no longer.
With an election due on 29 May, Shimon Peres, the prime minister, could not afford to look weak. His election slogan is: "Israel is strong with Peres."
Pressure to do something against Hizbollah had been building up in Israel during the Passover holiday. On Tuesday guerrillas fired seven Katyusha rockets into northern Galilee, injuring 36 people and damaging 200 homes in Kiryat Shmona, close to the Lebanese border. Mr Peres was advised not to visit the town for fear of hostile demonstrations.
The Israeli army offered the government three options: mass air attacks, a mixture of air and ground attacks, or an attack on targets in Beirut. Mr Peres appears to have opted for the first and third options. By launching the first air attack on Beirut since the 1982-84 Israeli invasion of Lebanon, he hopes to convince the Israeli electorate Hizbollah is being punished.
Government ministers in Jerusalem were yesterday sounding bellicose. Ori Orr, the defence minister, said: "Beirut itself must understand that it cannot be quiet there and less quiet in Kiryat Shmona." Major General Amiram Levine, in command of Israeli forces in Lebanon, said: "Residents in south Lebanon who are under the authority of Hizbollah will be hit harder and Hizbollah will be hit harder."
There was a more muted analysis from other members of the government. Yossi Beilin, a cabinet minister in Mr Peres's office, said there would be no drastic change in the situation at the border until Israel had a "comprehensive diplomatic agreement with Syria and Lebanon". The air attacks so far have been light, probably designed more as a warning than a serious military assault.
The danger for the government is that Hizbollah will strike back both against Israeli troops in their occupation zone in southern Lebanon and through Katyusha rocket attacks against northern Israel. The guerrillas have shown in recent months that they effective at evading Israeli patrols and staging complicated ambushes. The Israeli explanation for this is that Hizbollah has set up special units which have good intelligence and are highly trained.
There were several signs of this increased sophistication in recent weeks. In one instance a Hizbollah unit fired shots at a patrol on the Israeli side of the border and then killed four soldiers who pursued them with a mine; a senior Israeli officer was targeted by a suicide bomber; and a bomb was placed in the local office of the South Lebanon Army, the local Lebanese militia armed and trained by Israel.
All this is in sharp contrast to the military incompetence of the Palestine Liberation Army when it ruled south Lebanon before the 1982 invasion. Though its forces numbered about 6,000 - while Hizbollah forces are probably in the hundreds - it failed to mine the roads or bridges. Hizbollah has proved a much tougher antagonist and, as one Israeli observer put it, "Peres cannot afford another 20 military funerals."
Israel's opponents are far more skilled than they used to be, but Israeli tactics have remained much the same. Air attacks on Beirut and Baalbek and reported shelling by gunboats are an old recipe which has not proved very effective.
One possible innovation in Israeli tactics is to target villages from which Katyusha rockets are alleged to have been fired. Israel might announce that Hizbollah must leave certain villages by a certain date or Israel will feel free to fire at them.
If it does so this will mean the end of the understanding, brokered by the US in 1993, whereby Israel and Hizbollah pledge not to hit each other's civilians except by way of retaliation.
This would mean an escalation in Lebanon just when the Israeli government does not want it. In 50 days it will face a general election. It had hoped that Lebanon would not become an issue. It has enough troubles calming public anxiety over the four suicide bomb attacks which killed 62 people in February and March.
But an editorial in the daily newspaper Ha'aretz said a breaking point was close in northern Israel when "the population will move southward and, in politics, voters will shift to the right".
The air strikes yesterday were an attempt to achieve three aims: Show Israelis that firm action is being taken, send a warning to Hizbollah but, at the same time, not escalate the level of fighting. The extent of Hizbollah retaliation will decide if Mr Peres has achieved these contradictory objectives.