MIAMI — Marco Rubio and David Rivera charted a rise in this city’s famously scrappy politics together.

Both sons of Cuban immigrants, they befriended each other as campaign volunteers in the 1990s and climbed the ranks of local politics side-by-side. As young state legislators, they bought a house together near the capital in Tallahassee, where they orchestrated Rubio’s rise to Florida House Speaker and then launched winning bids to Congress.