Hamas's refusal to condemn the Tel Aviv bombing will have only reinforced the view of many in the West that the new Palestinian government must be treated as a pariah.
By Alan Johnston
BBC News, Gaza
Hamas appears ready to let other groups attack Israel
The attack at a busy food stall, carried out by the Islamic Jihad organisation, left nine people dead.
The United Nations Secretary General, Kofi Annan, called on the Hamas administration to take a clear stand against "unjustifiable terrorism".
US President Bush's spokesman accused the government of defending a "barbaric" act. And the Russians too said that the carnage in Tel Aviv could not be justified.
But there is no sign that Hamas feels in any way chastened.
After the West had delivered all its criticism, interior ministry spokesman Said Seeyam reiterated his government's view that the Tel Aviv attack constituted self-defence.
"We are not a great power that can confront the planes and missiles of the occupation," he said.
"But our people have the right and the will to defend themselves and confront as much as they can the arrogance of the occupation."
Mr Seeyam and his government know that - certainly on this issue - they have the backing of the streets of Gaza.
A man selling sheets in a shop off Palestine Square said: "The world ignores us. But through [the bombing] they will know that we are still alive and resisting.
"We have to continue in the right way - the path of Jihad."
And a food stand owner, Talat Hejazi, described his reaction to the news of the blast in Tel Aviv:
"I was very happy because of all these blows on us all the time. Let them feel it for once. Let them retaliate - we will sacrifice ourselves."
Overwhelmingly people spoke in those terms. But there were a few who expressed deep reservations, like Nadr Kitnani, who sat on the pavement trying to sell shoes.
"We are really afraid of the Israeli reaction because always their reaction is strong and we want to live," he said.
"We need to eat and drink. We have kids."
But however harsh Israel's retaliation might be, for now at least nobody here imagines Hamas revising its attitude towards attacks on Israel.
Islamic Jihad claimed the attack and released video of the bomber
What it describes as the right to resist is a central plank in its ideology. And cafes and buses and women and children can be targeted.
Hamas's message is that as long as there is occupation Israel will not enjoy security.
The movement regards all of Israel as occupied Palestinian land. But it has said that it would consider a long-term truce in return for a complete Israeli withdrawal from the West Bank, East Jerusalem and Gaza.
Hamas itself has largely observed a ceasefire for more than a year. Its focus now is on trying to consolidate its control of the government, and starting to reform many areas of Palestinian society.
But Hamas sees other militant organisations as being entitled to launch attacks if they choose.
The movement used to heap contempt on the previous Palestinian government - led by the Fatah party - for its occasional efforts to prevent militant activity.
The old administration was sometimes seen here as playing the role of "Israel's policeman".
And Hamas's armed wing has made very clear that it would not be prepared to obstruct groups like Islamic Jihad in the course of attempts to attack Israel.