One man has struggled to rein in a fractious tea party wing of his party, another harnessed those tea party-affiliated voters to become Mitt Romney's most formidable challenger, and the last could be standing where Romney is in 2016.

The tightly scripted events of the Republican National Convention are unlikely to yield any surprises on Tuesday, but the roster of speakers offers a glimpse of how the party is evolving and struggling to incorporate various factions.

Speaker of the House John Boehner (R-Ohio), who will be speaking at 7 p.m., understands those dynamics well. The 2010 wave election that gave Republicans control of the House of Representatives -- and Boehner the speaker's gavel -- has also produced rare displays of dissension within a party famed for its discipline and unity.

Never was that more evident than during the debt ceiling negotations of last summer, when recalcitrant new members helped to undercut Boehner's attempts to strike a deal with Democrats. Tea party groups even pledged to campaign against Republicans who supported Boehner's proposal.

Boehner later acknowleged that he was leading a "pretty disparate caucus" and likened his members to "218 frogs in a wheelbarrow." Those amphibious Republicans, intent on shrinking government and resistant to compromise, will continue to shape how Congress does business -- and as primary victories by tea party-backed Republican candidates like Ted Cruz in Texas and Richard Mourdock in Indiana show, more conservative Republicans remain a force with voters.

Rick Santorum's ability to appeal to more conservative-minded, tea party-sympathetic voters allowed him to endure as Romney's last rival for the Republican nomination. For his efforts, the former Pennsylvania senator and prominent social conservative will also be rewarded with a speaking spot on Tuesday.

Romney struggled to win over more conservative voters throughout the primary campaign, with voters in search of an alternative flitting from Rick Perry to Newt Gingrich to, finally, Santorum. Despite Romney's eventual victory, the rift endures -- and, should Romney lose, it is possible that Republicans will rue having gone with the safe choice. That could leave an opening in 2016 for candidates like Santorum, who disdain moderation in favor of red-meat rhetoric.

If Romney loses in November, all eyes will be on New Jersey Governor Chris Christie. Conservative pundits implored the tough-talking Republican to jump into the race this year, and his status as a rising star who embodies the party's cost-cutting ethos is secure. Christie's keynote address, starting at 10 p.m., will also serve as a kind of national coming-out party.