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ABC News' Michael Falcone reports:

Former Florida Gov. Jeb Bush told a gathering of Christian conservatives this morning that he was "sick to my stomach" about the slow pace of the U.S. economic recovery and outlined a four-point plan for speeding it up.

Among the points was immigration overhaul. And one of Bush's arguments in discussing his support for the Senate's version: "Immigrants are more fertile."

"Immigrants create far more businesses than native-born Americans," Bush declared at the Faith and Freedom Coalition conference in Washington. "Immigrants are more fertile, and they love families, and they have more intact families, and they bring a younger population. Immigrants create an engine of economic prosperity."

Indeed, the argument about the fertility rate of immigrants has gained traction among some conservatives. And President Obama's outgoing chairman of the Council of Economic Advisers, Alan Krueger, said at a U.S. Hispanic Chamber of Commerce event earlier this year: "Given current trends, nearly all of the growth of the nation's working-age population in the next 40 years will be accounted for by immigrants and their children."

Bush, a potential 2016 Republican presidential contender, also touted his support for immigration overhaul Thursday at a Bipartisan Policy Center panel. But he found himself at odds at today's event with fellow Republican Michele Bachmann, the Minnesota congresswoman and 2012 presidential hopeful who urged other members of her party to take a go-slow approach.

Bachmann, who recently announced she would forgo a re-election campaign next year, cautioned that immigration overhaul was making its way through Congress with "breathtaking speed." And although she insisted that she was not delivering an "anti-immigrant speech," she warned that amnesty "will cost a fortune."

Speakers at the three-day Faith and Freedom gathering addressed a wide range of issues, including Sen. Marco Rubio and Sen. Rand Paul's Thursday lament about the persecution of Christians around the world, former Sen. Pennsylvania Rick Santorum's assessment of what went wrong for Republicans during the 2012 election cycle, and Rep. Paul Ryan's values-based appeal today.

"Faith isn't a Christmas ornament," the 2012 vice presidential nominee told the audience. "It's not something that you take out on a seasonal basis."

As Republicans grapple with an internal tug-of-war on the direction of the party, Faith and Freedom Coalition founder Ralph Reed pushed back on what he called the "emerging consensus that we're the problem."

When it comes to opposition to abortion rights and gay marriage, Reed argued, "We cannot and we will not be silent - not now, not ever - because our faith requires us to speak to it."