Who is Trump's likely Republican successorVice President JD Vance has emerged as President Donald Trump's undisputed political heir for 2028, according to an Axios analysis, following a summer that saw him broker a tentative Iran peace deal, publish a bestselling book and embark on a media blitz that has impressed the current US President."JD is earning it, and Trump sees it," a senior Trump adviser told Axios, adding that Secretary of State Marco Rubio, the other top Trump aide seen as a potential heir, "wasn't planning to run anyway, and he'd be even less likely to do so now."For months, Trump has compared and almost pitted Vance and Rubio against one another, asking advisers whom they'd prefer at the top of a 2028 ticket. That parlor game is now on hold. "POTUS isn't asking, 'JD or Marc