Why has Israel launched the deadliest attacks on Palestinian territory since the 1967 Six Day War?

Israel's onslaught is a reprisal for a week-long barrage of rocket and mortar attacks from Gaza. Israel says it had to safeguard the lives in towns bordering the strip. Palestinians, and many others, believe the Israeli Prime Minister Ehud Olmert also ordered the raids to achieve what his government had failed to achieve through other means: the removal from power of Hamas, the Islamist political movement elected to run Gaza in 2006, which it accuses of being controlled by Iran and Syria.

Was the timing a surprise?

The scale and ferocity of the attacks came as a shock to many but tensions had been building after the expiry on 18 December of a ceasefire.

Why did the ceasefire collapse?

Hamas had offered to renew the ceasefire if Israel reopened Gaza's border crossings. The strip had been sealed by Israel in an economic siege aimed at toppling Hamas. The blockade has brought the territory near economic collapse.

Are Israeli domestic politics a factor?

Very much so. Israel is preparing for general elections on 10 February. The prospect of a return to power by the hawk Benjamin Netanyahu, leader of the right-wing Likud party, promising tough action against Hamas, has hardened the positions of Israel's more moderate political leaders.

Can Israel achieve its security aims by attacking Hamas so forcefully?

It is difficult to see Israel's action as being anything other than counterproductive, particularly if it escalates and widens the assault. Unless a fresh truce can be negotiated quickly, the hopes raised by the election of Barack Obama to the US Presidency and the possibility of a more engaged US policy seem to have dimmed again.