US Vice President JD Vance has taken on the role of the Trump administration's global attack dog, inserting himself into world events and making in-your-face comments that represent a departure from his predecessors. Vance triggered a row with Ukrainian leader Volodymyr Zelensky in the Oval Office and was dispatched to Greenland to back up Trump's territorial claims. He has been described as the most influential vice president since Dick Cheney and has been vocal about his skepticism on US aid for Ukraine. Vance's role is seen as a stepping stone for the highest US office, and he has admitted that he could run for president in the 2028 election.