Democratic presidential candidate Elizabeth Warren offered a public apology Monday to Native Americans over her past claim to tribal heritage, directly tackling an area that’s proved to be a big political liability. “Like anyone who has been honest with themselves, I know I have made mistakes,” the Massachusetts senator said at a forum on Native American issues in this pivotal early-voting state. Now that Warren is gaining in most polls, she’s trying to prove to voters that the controversy won’t doom her in a general election matchup against Trump.