A year ago, the stage seemed set for Vice President JD Vance to succeed President Donald Trump as the MAGA heir apparent in 2028. Vance, just 40 years old at the time of the 2024 election, came into office with wave of support from Republicans and the backing of the president's family. And while the vice president remains well-positioned ahead of a likely 2028 campaign, questions are quietly emerging over Vance's inevitability, especially as Secretary of State Marco Rubio’s profile and responsibilities have grown throughout the first year of Trump’s second term, most recently around the war with Iran. The...