Is there a direct connection among the recent string of security incidents - the murder in Itamar, the escalation around the Gaza Strip, the Grad rockets on Be'er Sheva and the terror attack in Jerusalem? That was one of the questions occupying defense and government officials on Wednesday.

At this point, the answer is still unclear.

In any case, the bombing in Jerusalem cut short a period of almost three years of calm in the capital. It is a significant turn for the worse for the city, which managed only with great difficulty to extricate itself from the second intifada.

The perpetrators of Wednesday's bombing in the capital apparently took advantage of changes in Israel's security deployment in the West Bank and Jerusalem, which stemmed from the prolonged quiet. Security checks at the separation fence, at checkpoints and in city centers have become much less thorough, while the Israel Defense Forces presence in the West Bank has been pared down.

Moreover, since the old terror networks have mostly been dismantled, the Palestinian Authority has been making most of the arrests, so Israeli intelligence operatives have less daily contact with the field.

Wednesday's bombing in Jerusalem was limited in scope. A suicide bomber was not involved, and the bomb was relatively small. The pattern is different than the one Hamas used during previous waves of terror.

The bombing may have been a local initiative. As of last night, no terrorist group had claimed responsibility for it or even praised the perpetrators.

Despite the escalation, Hamas does not seem to want large-scale clashes yet. The organization actually has good reasons to believe that Israel is the one heating up the southern front. It began with a bombardment a few weeks ago that disrupted the transfer of a large amount of money from Egypt to the Gaza Strip, continued with the interrogation of engineer and Hamas member Dirar Abu Sisi in Israel, and ended with last week's bombing of a Hamas training base in which two Hamas militants were killed.

It is noteworthy that Hamas has not fired at Israel over the past two days, even after four Palestinian civilians were killed by errant IDF mortar fire on Tuesday.

Hamas Prime Minister Ismail Haniyeh's office said yesterday that Haniyeh had phoned the secretary general of Islamic Jihad, Abdallah Ramadan Salah, in Damascus. Pundits in Gaza said Haniyeh asked Salah to stop the escalation, for which Islamic Jihad is mainly responsible.

Islamic Jihad has chalked up quite an achievement over the past few days. If at one time endless barrages of Qassam rockets were needed to threaten Israel, Jihad's Grad rockets from Iran have changed the rules. It only took a few Grads to raise the level of anxiety in Be'er Sheva and Ashdod.

Palestinian Authority President Mahmoud Abbas and PA Prime Minister Salam Fayyad harshly condemned the bombing in Jerusalem yesterday. The PA seems quite disconcerted by the recent attacks, which undermine its attempts to brand the Palestinian struggle as nonviolent.

Apparently, lacking an address for the attacks in Itamar and Jerusalem, Israel will focus on Gaza. But the response will apparently not be extensive, so statements like those by Vice Prime Minister Silvan Shalom yesterday - that "the period of restraint has ended" - should be taken with a grain of salt.

Prime Minister Benjamin Netanyahu did speak out strongly yesterday, but in his two years in office, he has been very careful when it comes to military action. Netanyahu left for Russia last night, and today, U.S. Defense Secretary Robert Gates arrives in Israel. Such a diplomatic schedule limits Israel's ability to act.

Netanyahu spoke of "an exchange of blows." It seems Israel wants to strike the last blow in this round and then declare a halt. The concern is that Islamic Jihad will refuse to play by Israel's rules.

And if Israel's goal is to go back to the rules in force in Gaza a few weeks ago, how much force is it worth using to get there?