the federal government to act, said the ruling was a victory because it left in place the measure at the "heart" of the legislation. The decision to strike down most of the law leaves Republican presidential candidate Mitt Romney in an awkward position, not least because he has publicly suggested that Arizona's approach was a model for the nation. Romney, who is visiting Arizona on Monday and will almost certainly be asked about the ruling, said: "I believe that each state has the duty -- and the right -- to secure our borders and preserve the rule of law, particularly when the federal government has failed to meet its responsibilities. As a candidate Obama, he promised to present an immigration plan during his first year in office. But four years later, we are still waiting. "I would have preferred to see the supreme court give more latitude to the states, not less. And there are states now under this decision that have less authority, less latitude to enforce immigration laws." Members of the media gather in front of the US supreme court in Washington ahead of a set of anticipated rulings. Photograph: Yuri Gripas/Reuters Over the past two weeks Romney has found himself outmanoeuvred by Obama on the immigration issue. Obama has a built-in advantage of a two-to-one ratio of support among Latinos and polls suggest he has widened the gap since his announcement a week ago on Friday to lift the threat of deportation for an estimated 800,000 undocumented