It’s a new day for Rick Perry: the Texas governor will endorse a national, optional flat-tax rate of 20 percent in a speech in South Carolina on Tuesday, one day after he announced several new hires to his flagging presidential campaign. The new staffers include senior adviser Joe Allbaugh, who was George W. Bush’s 2000 campaign manager and a close associate of Karl Rove. Perry’s campaign will also begin to run television ads in Iowa this week.