PHILADELPHIA, Pennsylvania: The Democratic Party kicks off its national convention on Monday to anoint Hillary Clinton its presidential nominee, amid a simmering row over leaked emails that show party leaders sought to undermine campaign rival Bernie Sanders. Sanders lost the primary race but he has endorsed his bitter rival, and in a show of unity he has been offered a prime speaking slot on day one of the four-day confab. Sanders will stress that the party mission is to elect Clinton in November and prevent billionaire Republican Donald Trump from becoming the 45th President of the United States. But while the former secretary of state is set to make history as the first female flag-bearer of any major American political party, the process has fallen under a cloud that Trump was all too eager to exploit. Anti-secrecy website WikiLeaks at the weekend released nearly 20,000 emails from between Jan. 2015 and May 2016, gleaned by hackers who apparently raided the accounts of seven Democratic National Committee leaders.