President Ronald Reagan (R-CA) / Vice President George Bush (R-TX) ✓
Senator Joe Biden (D-DE) / Senator Gary Hart (D-CO)
It's difficult to see an opening for Biden in the primaries to begin with- Mondale had New Dealer labor, Hart had the younger, tech-friendly, business-friendly Atari Democrats- but I'm guessing Biden runs like a better version of Hart with just enough Rust Belt/developing Farm Crisis appeal to pull off an upset. He and Hart win over Kennedyland, but given the quality of Biden's campaigning, I don't think he could sell himself as a populist insurgent and really make inroads in the Midwest. It was too early for the Republican Lite strategy, so that door is closed too. All a Biden (or Hart) primary upset really achieves is making the Democrats' disarray look worse, because neither had a substantiative alternative to Mondale's New Dealerism or Reagan's neoliberalism, just platitudes about newness and youth ("where's the beef?").
Reagan would also still have been able to use the "youth and inexperience" line against Biden, which definitely handed him the election, as Biden had less experience than even Mondale.
