Axelrod and Messina - both of whom will work remotely from the US during the UK campaign - are hardly Britain's first electoral imports.
"There's a fruitful transatlantic trade in political expertise," says Nick Anstead of the London School of Economics.
In addition to Messina, the Tories have also brought on Lynton Crosby, a political consultant described as the "Australian Karl Rove."
Labour has been borrowing US campaign strategies since at least 1992, when party operatives flew to Little Rock, Arkansas to meet with Democratic advisors after Bill Clinton's victory.
"When you hire someone like David Axelrod, you're hiring an idea of how politics should be done," Anstead says - in this case, the shoe-leather, grassroots campaigning the Chicago operative favors. "It will be interesting to see how that is imported."
How much Americanization takes place in British politics will be influenced by the public's expectations of politicians, which significantly differ from US attitudes.
The earnest, over-the-top patriotism Americans have come to expect of presidential candidates would trigger gag reflexes among many British voters. Unlike most of their US counterparts, MPs don't sport pins of their national flag on their lapels.
And while American politicians seemingly can't get elected without repeated references to their faith in a Christian God, most Brits don't need - or want - their politicians to get personal about religion.
"People in the UK do not vote with their ballot papers in one hand and their Bibles in the other," says Eliza Filby, a lecturer at King's College London and author of the forthcoming book "God and Mrs. Thatcher."
"We are not a nation that likes or requires a leader to speak openly about religion, or even be an active believer," she adds.
Of the three main party leaders, the Liberal-Democrats' Nick Clegg is an atheist, Labour's Ed Miliband identifies as a "Jewish atheist" and Cameron once compared his ambivalent Christian faith to the spotty radio signal in the countryside.
Few voters care.
Leaving aside Margaret Thatcher's impromptu recitation of the Prayer of St. Francis on the day she took office, politicians and their advisors have shied away from overt references to their faith in recent history.
When then-Prime Minister Tony Blair was asked about his religion during a 2003 interview, his spokesman Alastair Campbell butted in to say, "We don't do God."
And when Blair proposed ending a speech with "God bless Britain" a few years later, a staff member shot him down with a curt, "I just remind you prime minister, this is not America," Blair recalled in 2012.
So when Cameron remarked in a speech last month that Britain should not be afraid to identify itself as "a Christian country," it took many people by surprise. It seemed so ... un-British. So American.
Cynical observers noted that Cameron's remarks expediently pushed the embarrassing resignation of a Tory minister out of the headlines, proving that co-opting God for political reasons works just as well on both sides of the Atlantic.
"There was clearly a hole in the ‘grid,' the need for a new talking point," Alastair Campbell wrote on his blog, "so someone said ‘I know, let's get Dave to do God.'"
