Rick Santorum withdrew from the race for the Republican Party's presidential nomination. His announcement was unexpected, and came after he assured supporters that he would continue campaigning despite pressure from party bigwigs to pull out. Mr Santorum gave no one specific reason for his exit, though his three-year-old daughter, who has a rare bone disease, has been in and out of hospital. With Mr Santorum's departure, Mitt Romney became the presumptive Republican nominee (Newt Gingrich and Ron Paul are too far behind to catch him now). The general-election campaign stepped up a gear; Barack Obama spent much of the week promoting his proposal that the rich should pay at least 30% of their income in taxes. In a landmark ruling on extraditions, the European Court of Human Rights agreed that Abu Hamza, an Egyptian-born Muslim cleric who is based in Britain, and four other suspected Islamists could be sent to the United States to face terrorism charges. The men had argued that they would be treated inhumanely if they were sent to America. American officials said the trial of Khalid Sheikh Mohammed and four others accused of planning the 9/11 terror attacks would resume next month at a military tribunal in Guantánamo. Legal proceedings against the men have been in limbo ever since the government abandoned its attempt to have them tried in a civilian court in New York. Viktor Bout, a notorious Russian arms dealer known as the Merchant of Death, was sentenced to 25 years in prison by a judge in New York. A state prosecutor in Florida brought a murder charge against George Zimmerman, a Hispanic man, for the killing in February of Trayvon Martin, a black youth. The case has caused controversy, and many protests around America, as local police did not charge Mr Zimmerman, citing Florida's "stand your ground" law. Mr Zimmerman says he shot Mr Martin in self defence. America's superpowers Dilma Rousseff, Brazil's president, went to the United States to meet Barack Obama. They agreed to improve co-operation on defence and discussed trade and energy policy. The European Union banned Conviasa, Venezuela's state airline, from operating in its member states, because of concerns over its safety record. Hugo Chávez, Venezuela's president, returned from Cuba after more medical treatment. He had said that he was cured before announcing in March that the cancer had returned. Despite his illness he is running for re-election; voters head to the polls in October. Spilling over Turkey protested to Syria after its forces opened fire on Syrian refugees who were crossing the border, killing at least two people. Around 24,000 Syrians have crossed into Turkey to escape the turmoil in their country. The regime continued its crackdown by shelling rebel areas. A ceasefire brokered by Kofi Annan, a former UN secretary-general, started on April 12th, though many observers doubt it will hold. Iran said it would offer new proposals over its contentious nuclear programme at talks with six foreign powers that are due to resume in Istanbul on April 14th. Joyce Banda, Malawi's vice-president, succeeded President Bingu wa Mutharika, who died following a heart attack. Ms Banda is expected to take the country in a more liberal direction. The African Union demanded that South Sudan withdraw its troops from the Heglig oilfields controlled by Sudan. The two countries appear perilously close to all-out conflict. An Egyptian court suspended the constitutional assembly ahead of presidential elections in June. Omar Suleiman, the right-hand man of Hosni Mubarak, the toppled dictator, announced his candidacy. The intrigue deepens Bo Xilai, a former rising star in China's Communist Party who was removed as head of the province-level municipality of Chongqing last month, was suspended from the Politburo. His wife, meanwhile, was detained on suspicion of murdering Neil Heywood, a British businessman found dead in Chongqing last November. The scandal has rocked China's political class. Asif Ali Zardari, Pakistan's president, met Manmohan Singh, India's prime minister, in Delhi, the first visit by a Pakistani head of state in seven years. Mr Zardari was in India for a private trip to a Muslim shrine. During his visit, an avalanche at the Siachen glacier, where India and Pakistan have stationed troops, killed over 130 Pakistanis. Navy ships from China and the Philippines faced off at the Scarborough shoal in the South China Sea. The Philippine ship was trying to arrest Chinese fisherman when a Chinese surveillance vessel blocked them. Both countries assert sovereignty in the area. President Lee Myung-bak's governing party kept its majority in South Korea's parliamentary election. The liberal-left opposition had hoped to gain from a number of corruption scandals that have afflicted the government. On polling day North Korea reasserted its intention to launch a satellite, against UN restrictions. Bossi booted Umberto Bossi, a veteran of Italian politics, resigned as leader of the Northern League, an opposition party. Prosecutors in Milan allege that taxpayers" money supplied to the party was spent on Mr Bossi and members of his family, who deny wrongdoing. To widespread criticism Günter Grass, a German Nobel literature laureate, published a portentous poem attacking Israel for its aggressive posture towards Iran. The Israeli government promptly banned Mr Grass from visiting the country. Lucas Papademos, Greece's prime minister, called a general election for May 6th. Polls suggest that many fringe groups may enter parliament. In his last speech to the Duma as Russia's prime minister, Vladimir Putin, the president-elect, said he would work to improve the investment climate. He also hinted he might support a law barring presidents from serving more than two terms. Mr Putin begins his third presidential term on May 7th; such a law, he said, would not be retrospective.