Donald Trump should focus on bringing in Bernie Sanders voters and on attacking Democrat Hillary Clinton as the ultimate insider, political pundit and author Dick Morris said Monday on Fox Business Network's GOP convention coverage.Morris is author of the new bookwith Eileen McGann, and told Fox's Maria Bartiromo that the presumptive GOP nominee's "left hook" is to woo fans of Clinton's Democratic rival, Sen. Bernie Sanders.By echoing the same critique of Clinton that Sanders had — that the big banks bankrolling and controlling Clinton — Trump has "a very good chance to get the Sanders vote."Trump, who is making his first run at political office, should also paint Clinton, a former first lady, U.S. senator and secretary of state, as the ultimate insider and not focus on her being a liberal Democrat, said Morris, who worked for the Clintons in the 1990s."I saw the Hillary Clinton that you've seen, but I saw it 20 years earlier, 40 years earlier," he said. "I saw the lying and the scandals. I remember one time saying in the White House, 'Every scandal I'm trying to defend for Bill, Hillary caused.' And I just don't think she should be president."Though both Trump and Clinton have high "untrustworthy" numbers, Morris made a distinction:"Donald Trump is in trouble for the things he's said, Hillary is in trouble for the things she's done," he said. "You can unsay what you've said, but as far as to undo what you've done…."Asked by Bartiromo about how unusual it is for a major presidential party nominee to be under investigation, Morris responded: "It's not like it's unusual: When was she not under criminal investigation?""She's skated by four grand juries in her time," he noted, but added that he thinks her use of a private email server to send and receive classified information will do more damage than her previous scandals.Morris also advised Trump to use his negatives as positives.Trump should say, "The Clintons are against me and the Bushes are against me. I'm against the monopoly of politics by these two parties that doesn't care what the people think. And if you want proof of my bona fides ask the Bushes," Morris said.Trump should expect the normal 10 percent convention bump in the polls, Morris said, but added that Clinton will likely follow up with her own 10 percent bump after next week's Democratic convention. If Trump doesn't get the bump and Clinton does, it could put him in trouble going into Labor Day, he said.Morris also said he'd like to see the convention focus less on Trump's family – all of his children and his wife will speak on different nights of the convention. There should be more focus on the GOP message, he said.Morris's bookis available at bookstores and online at bothand