Asif Ali Zardari, Pakistan's president, has rejected calls for him to resign from office after the nation's top court struck down an amnesty protecting him from corruption charges.<br /><br />The Supreme Court ruled on Wednesday that a law allowing Zardari amnesty from criminal charges was null and void.<br /><br />Zardari has insisted that the charges are politically motivated.<br /><br />But as Imran Khan reports, pressure is mounting on the president to quit.