Although most defense-related declarations in the first weeks of the election campaign have focused on the Iranian threat, the gradual escalation on the Gaza border now seems the main cause for concern. It may eventually become a political risk for Prime Minister Benjamin Netanyahu.

Netanyahu isn't looking for a broad military conflict with Hamas in the Gaza Strip. It's also hard to believe that Hamas wants one. And yet events of recent weeks are bringing Israel and Hamas closer to a clash that could cast a heavy shadow over the election.

On Monday morning 20 rockets were fired from Gaza into Israel. No one was injured in the barrage, for which Hamas has taken responsibility. In response, the Israel Air Force struck targets linked to Hamas in the Strip, and no one was injured there either.

In Hamas' renewed fervor to stand up to Israel militarily, it shot itself in the foot, as it were, when it distributed films showing rockets being launched from the heart of populated areas. Thus it uses civilians as shields, just as Israel has claimed all these years.

Unlike during previous rounds, the events of the past two weeks have clearly been initiated by Hamas. The group is now taking an active role in the violence and isn't afraid to say so. Hamas is trying to create a balance of fear under which any action by Israel on the other side of the fence or even next to it will carry a price tag.

Every time Israeli troops cross the fence to find and dismantle explosives set by the Palestinians, Hamas activists fire mortars at them. Hamas claimed responsibility for placing the explosive charge near the fence that seriously injured Cpt. Ziv Shilon last week.

But so far, Hamas has lost at least four of its men, without causing any damage in Israel. If the violence continues, it will put the organization in a dangerous situation.

So far the Israeli response has been restrained - targeting crews of Hamas or the more extreme organizations that are launching rockets. But this could change if the rocket fire persists. The government, under election-season pressure and amid the pictures of the communities near Gaza, has approved the reinforcement of buildings up to seven kilometers from the Strip. The government won't be able to stop at this if the nightly news continues to open with pictures of Negev residents fleeing for shelter.

This is all apparently directly linked to the bombing of the weapons plant in Sudan last week, an action Israel refuses to comment on despite direct accusations by Khartoum. Aerial photographs show precise hits on shipping containers, while buildings remained undamaged, strengthening the suspicion that the goal was to destroy equipment that had been smuggled recently to Sudan, not weapons manufactured in the factory itself.

According to foreign sources, the factory belongs to Iran's Revolutionary Guards, who have led other weapons convoys that have been bombed over the past four years. Sudan is an essential stop on the smuggling route from Iran to Gaza. But there could be another consideration: If the Iranians are bringing equipment into Sudan in parts and assembling it there, there is less of a chance of catching them contravening international bans on weapons smuggling.

For Israel to risk making an attack 1,900 kilometers away, the bombed convoy would have to contain "tiebreaking" weapons. What are they? One possibility is surface-to-sea missiles, the kind Israel's navy caught in the Mediterranean aboard the Victoria, smuggled from Iran 18 months ago. Or they could be unmanned aerial vehicles like the one Hezbollah launched over Israel a few weeks ago.

In any case, Iranian naval ships were docked at a Sudanese port yesterday. This was probably a voyage planned long in advance, yet it can be seen as a message to Israel: The smuggling will continue.