TEL AVIV, 17 July 2006 — What began as a pair of hasty military incursions aimed at getting back captured Israeli soldiers has evolved with breathtaking swiftness into a full-blown campaign by Israel against two of its bitterest enemies, the Islamist groups Hezbollah and Hamas.

In both instances, Israeli and outside analysts say, Israel has embarked on a risky strategy that has two major elements: The use of overwhelming military force to reduce the opponent’s power coupled with strikes that hurt the wider civilian economies and populations of Gaza and Lebanon. The aim of the second part of the strategy is to put pressure on more moderate elements of the Palestinian and Lebanese governments to strip Hamas and Hezbollah of some of their influence and prestige.

In Gaza, the fighting had gone for roughly a week before it became clear that the goal of the military operation had widened well beyond the efforts to stop Hamas from lobbing crude Kassam rockets into southern Israel and to free Cpl. Gilad Shalit, the captured 19-year-old tank gunner.

Soon after the offensive began, commentator Roni Shaked wrote in the Yediot Aharonot newspaper that Israel had a “golden opportunity.’’ Whether or not the operation succeeded in freeing Shalit, “by crushing the Hamas regime, Israel can accomplish a much greater strategic step, which could have a profound effect on the entire region,’’ he wrote.

Within days, Israeli policymakers were speaking openly of their hopes to use the confrontation to drive Hamas from power.

Israeli leaders were far faster to see the tantalizing glitter of such opportunity in Lebanon.

Hamas has only been in power in the Palestinian territories since January. Hezbollah has dominated southern Lebanon for years, and the Israeli Army has long worked on plans for striking it if the right moment presented itself.

Only hours after Hezbollah fighters last Wednesday staged a cross-border raid in which they killed eight Israeli soldiers and captured two, Israeli leaders began to talk of dealing the militant movement a devastating blow from which it could recover neither politically nor militarily.

From across the Israeli political spectrum, such declarations are now being made on a daily basis. “We must eliminate, destroy and crush all of Hezbollah’s infrastructure,’’ lawmaker Eli Yishai of the religious Shas party said Sunday.

“We intend to break this organization,’’ Defense Minister Amir Peretz, of the left-leaning Labor Party told journalists.

But the policy carries several risks.

Israel is uneasily aware that Hamas and Hezbollah now find themselves on common ground — squarely in Israel’s gun sight. That may strengthen ties between the two groups, who, despite common opposition to Israel, have previously been rivals.

The leader of Hezbollah, Sheikh Hassan Nasrallah, has spoken of trading all three Israeli captives — the two that Hezbollah claims to hold and the one held by Hamas-linked militant groups — for an unspecified number of prisoners in Israeli jails. Israel has rejected that demand.

A second major risk involves the deaths and injuries to civilians. In Lebanon and in the Gaza Strip, the Israeli military incursion has dramatically heightened daily hardship, and civilians are keenly aware that they bear the consequences when Islamist fighters choose to aim a blow at powerful Israel.

“When they fire a rocket from my orange grove, I want to ask them, ‘Why don’t you just aim it at me instead?’ ‘’

Bassam Daoud, a farmer in northern Gaza, said, referring to the Hamas fighters. “I will pay the price for what they do.’’ Daoud’s agricultural lands were laid waste earlier this month by Israeli troops seeking to stop Hamas from launching Qassam rockets.

But whatever resentment is directed at the guerrillas pales in comparison to the helpless fury that Gazans and Lebanese feel when confronted by the fierce firepower Israel has brought to bear in their backyards.

“We have to be realistic about what kind of result we are likely to get when we presume to ‘engineer’ the population’s attitudes, trying to make them run to their leaders and cry out for change,’’ said Uri Dromi, an analyst with the Israel Democracy Institute and a former Israeli government spokesman.

“Face it — we’ve had a really notable lack of success with that kind of thing in the past.’’

Shaul Mishal, a Tel Aviv University professor who studies militant Islamic movements, also questioned the benefit Israel would derive from taking its drive against Hezbollah to the bitter end. “Let’s say we crush Hezbollah, and Nasrallah’s body is floating in the water,’’ he said. “Are we really sure things will be better, or will Hezbollah simply split into a million pieces, like mercury?’’

It might be better, said Mishal, to take advantage of the fact that Hezbollah is a cohesive structure with a clearly defined leadership, which can make commitments and carry them out. By contrast, Hamas’ lines of authority are far more muddled with no one leader speaking for the movement.