Magazine publisher Steve Forbes plans to intensify his presidential campaign, hoping to emerge as the challenger to George W. Bush, who’s the front-runner for the Republican presidential nomination.Forbes says if elected, he would appoint “pro-life” justices to the Supreme Court who would overturn Roe-v-Wade. By comparison, Bush has said he wouldn’t impose such a “litmus test” on Supreme Court nominees.Forbes made campaign stops in Council Bluffs and Sioux City yesterday.