The shadow primary for the next presidential race is already underway as both parties ramp up this year’s midterm fight.  Potential Democratic contenders, from established names to rising stars, are openly weighing 2028 bids, signaling a wide-open field as their base searches for a new standard-bearer. Several top names, including former Vice President Kamala Harris, addressed the possibility at the National Action Network (NAN) conference last week as they pitched visions for their party’s future.  Across the aisle, Vice President Vance is positioned as the MAGA movement’s heir apparent, but recent polling and President Trump have suggested that Secretary of State Marco Rubio could be the successor, stoking questions about where the GOP base will go after more than a decade of Trump dominating party politics.  Here is The Hill’s latest roundup of the top 2028 presidential hopefuls: Democratic comeback bids Harris, who ran in 2020 and became the party’s pick in 2024, has remained at the fore of Democratic polling and chatter about who will lead the party in 2028 — and she’s openly admitted to considering a comeback bid. “Listen, …