It isn’t lost on Jeb Bush, or aides to his struggling presidential campaign, that the biggest threat to his candidacy doesn’t come from outside the Republican establishment, but from within. Before he tackles Donald Trump, he must first tackle the candidates competing with him for donor and official party support. At the top of that list is his former pupil, Marco Rubio.

Though Trump is the front-running candidate, and Bush’s most persistent antagonist, team Bush is less interested in assuring restless supporters that he has a plan to combat Trump than that they shouldn’t be tempted to throw their support to Rubio. “Marco is a GOP Obama,” Bush argued in a slideshow presentation to top donors in Houston this weekend. “Rubio and President Obama have strikingly similar profiles: first-term senators, lawyers and university lecturers, served in part-time state legislatures for eight years, had few legislative accomplishments, and haven’t shown much interest in the process of advancing legislation and getting results.”

To both his benefit and detriment, the Obama analogy has clung to Rubio since well before Bush raised it. Like Obama, Rubio is relatively inexperienced, but also like Obama, he’s young, charismatic, ethnic, and insurgent. This is why the comparison to Obama helps him with conservatives as much as it stings.

But to accept the Rubio-as-Obama line, you must ignore the vastly different strategic niches the two men occupy. In proper context, the Republican Party’s answer to Obama isn’t Rubio. It’s Trump. 

Obama’s charisma was key to his appeal in 2008, but so too was the fact that he—as a young, African-American liberal who opposed the war in Iraq—reflected his party’s base better than Hillary Clinton, the anointed front-runner. By this more appropriate standard, the GOP’s Obama will be charismatic, yes—but old and white and nativist instead of young and ethnic and cosmopolitan. That’s Trump. It explains the durability of his polling lead and the growing sense among Republican Party elders that he could actually win the nomination.

Republicans don't necessarily need an Obama of their own, though. They could also nominate someone with the skill and desire to reform the party in a way that makes it appealing outside the population of white conservatives. The big question for Rubio isn't whether he's an Obama clone, but whether he can do for Republicans what Bill Clinton did for Democrats, or whether he’ll adhere to orthodoxy and squander his potential.

The GOP has been at odds with itself for years now over whether the path to victory in national elections runs through maximizing white voter turnout or appealing to the policy preferences of non-white voters. Trump embodies the former theory, Rubio the latter—to a point. Rubio famously repudiated his own immigration reform bill and has foreclosed the possibility of making unauthorized immigrants eligible for citizenship during his presidency. But he’s also hedged and obfuscated enough on the issue that he could feasibly correct course again during the general election before his impression in immigrant communities fully settles. Likewise, and in contrast to most Republican candidates, he’s expressed empathy with black and brown people who have grown to distrust law enforcement, and has a real claim to understanding the challenges poor and working-class Americans face.

But Rubio is also making the most shallow appeal of any Republican in the field. The undisguised promise of his candidacy is that his youth and background will allow him to herald an orthodox Republican policy agenda as somehow distinct and visionary. Perhaps because his heterodoxies are so superficial, Rubio enjoys the support of only 23 percent of Hispanic voters, lower than the paltry share that voted for Mitt Romney in 2012.

In this way, Rubio resembles the Republican Party’s answer to John Edwards rather than a genuine reformer, like Clinton. Both Clinton and Edwards banked on their meager Southern upbringings—the man from Hope and the son of a mill worker, respectively—to appeal to culturally conservative, Republican-leaning constituencies. Clinton, who ran at a time when the Democratic Party needed to widen its appeal, and on a platform that genuinely deviated from party doctrine, became president. Edwards first ran as a second coming of Clinton in 2004, when Democrats were haplessly trying to out-warrior Republicans. He ran again four years later, at a moment when Democrats were ascendant, as a doctrinaire progressive with a Southern accent. He lost both times.

You can fairly boil down the GOP debate over whether to maximize white turnout or adopt more inclusive politics to the question of whether Republicans should be searching for their Obama or their Clinton. Both theories have surface plausibility. Trump is their Obama. So far, Rubio is neither their Obama nor their Clinton.

And Jeb Bush makes an even worse fit for either role.