Former Florida governor Jeb Bush has a big base problem. (Photo by Mark Wilson/Getty Images)

With his "shock and awe" roll-out, Jeb Bush has managed to push Mitt Romney aside and he is also steadily elbowing his way past New Jersey Gov.  Chris Christie among the high-roller set.

But whatever his momentum among the GOP establishment, that strategy has done nothing to tamp down the anti-Bush fervor among grassroots conservatives. In fact, it seems his gains have only inflamed the opposition, leaving Bush with a tough sell in states like Iowa -- among others. It's a much bigger problem for Bush than it is for Hillary Clinton, whose party is far less divided these days.

A pretty good encapsulation of Bush's base problem is a video called "Unelectable," put out by the tea party group ForAmerica, which tries to connect the dots between Bush and Clinton and Benghazi.

Unelectable from ForAmerica on Vimeo.

This is a clever video, linking Bush to what conservatives see as Clinton's biggest failure. The pairing echoes Rush Limbaugh's talking points about the event at the time. (As my colleague Jose A. DelReal wrote, Bush also has a talk radio problem.)

ForAmerica, while not exactly a big-name conservative group with a huge following, might be the first to highlight the comments in this format. But they certainly won't be the last.

The video captures the kind of guilt-by-association that is common in today's Republican Party, in which even saying nice things about political opponents is grounds for excommunication. And with Bush -- a proponent of Common Core and comprehensive immigration reform -- there's plenty of material there. A recent headline from the Daily Caller ("Jeb Bush Can Be Beaten") captures the sentiment of many grassroots conservatives.

Typically, an establishment candidate like Bush needs to find a connection with the base that will allow people to get past the impurities. For Romney, it was a hard-line stance on immigration and being the guy who could (supposedly) beat President Obama. For John McCain, it was his reputation as a hawk. George W. Bush excited evangelicals when he talked about finding God. And Clinton is now co-opting Elizabeth Warren's rhetoric, if not her speaking skills.

What's the sweet spot for Bush?

Well, it's not immigration or education, and it's probably not social issues, though he's got bona fides on those from his time as governor. Which leaves foreign policy, an area where Bush is on shaky ground because of his brother and his own lack of experience. Benghazi remains a huge issue for the GOP base, and this video suggests that Bush might even have trouble making the kind of case that the base wants to see him make on it. (Though, in fairness, Bush didn't really give an award to Clinton. The National Constitution Center, which he chaired, did.)

He has talked about a strategy based on losing the primary to win the general. Conservatives, desperate for one of their own, are starting to make the case that Bush's electability argument in the general also needs some work. It's all quite reminiscent of conservative criticisms of Romney, who eventually gave the base what it wanted.

But what Romney had -- as did McCain and Bush, to lesser extents -- was a lack of viable GOP alternatives. The 2016 GOP field is looking as if it will be packed with any number of viable alternatives for Republicans looking for a potential winner. Bush has pushed aside Romney and looks far superior to Christie, but that says nothing about folks like Scott Walker or Marco Rubio -- or even Rand Paul.

Bush has a tricky path ahead, with Democrats and grassroots conservatives both united in trying to trip him up before he reaches the finish line. And his starting point with the base isn't a good one.