Key Republican and Democratic senators, working to attract more support for President Bush's stalled immigration bill, huddled Wednesday with Homeland Security Secretary Michael Chertoff to discuss tougher border security and workplace enforcement. At a Capitol Hill meeting, the bipartisan group continued talks aimed at cobbling together enough backing from skeptical Republicans to quickly revive the measure that would grant legal status to as many as 12 million unlawful immigrants. A day after Bush fielded criticism from Republicans whose opposition derailed the bill last week, the White House said it would be open to changes to the delicate bipartisan deal. Architects...