Marco Rubio leads the Republican VP nominee 2028 market at 29.5% amid trader consensus that his role as Secretary of State has elevated his profile through ongoing diplomatic and foreign policy work. Current Vice President J.D. Vance sits far behind at 5.5%, consistent with positioning that favors a presidential bid instead. The rest of the field remains fragmented below 6%, with no other contender showing clear momentum. Key differentiators include Senate experience, alignment with party priorities, and potential for geographic or ideological ticket balance. Consolidation behind one name could hinge on signals from the Trump administration, results from the 2026 midterms, or early positioning that clarifies the presidential contest.