Washington — When voting began Thursday on whether to advance President Bush’s immigration bill, Kansas Sen. Sam Brownback was among the first lawmakers to vote “yes.” About 10 minutes later, Brownback switched his vote to “no.” But don’t bother accusing the Republican presidential hopeful of flip-flopping — he says he did it on purpose. “I wanted to signal that I support comprehensive immigration reform, but now is not the time, this is not the bill,” Brownback said. Brownback explained that his “yes” vote initially was to “showcase” that reform is needed. The switch to “no” was because he didn’t think...