A footnote to the pledge links to a series of articles written by the Center for Military Readiness. It's a socially conservative group that opposed allowing gays to serve openly in the military. But it also is against putting women on the front lines, suggesting that they endanger both themselves and their units.
"Where we're coming from is, it's ultimately going to be a probably more nuanced military decision by commanders, but the point is, the commander in chief, we are expecting to understand the wrong headedness of unnecessarily exposing women to the risks" outlined in the pledge, said Chuck Hurley, president of the Iowa Family Policy Center who helped author the pledge, in an interview with National Journal.
It's not the only politically explosive part of the pledge.
In arguing that the institution of marriage is under assault, Family Leader contends that by one measure African-American families were in better shape during slavery than now: African-American children were more likely to be raised in a two-parent household in 1860 than if they were born today, as the group put it, "after the election of USA's first African-American president."
The group also dismisses the belief that gays are genetically pre-disposed to their sexual orientation as the result of "anti-scientific bias" rather than empirical evidence.
Rep. Michele Bachmann, R-Minn., became the first presidential candidate to sign the Family Leader pledge Friday. Former Sen. Rick Santorum, R-Pa., also signed the pledge.
Her campaign spokeswoman Alice Stewart declined to speak specifically about provisions in it and the supporting document, but she said the congresswoman "supports each aspect of the pledge."
"She was happy to sign it," Stewart said.
The pledge creates a particularly acute dilemma for Tim Pawlenty, who has vowed to make Iowa a key part of his primary strategy. The former Minnesota governor has tried to appeal to both grassroots activists and establishment party figures. His decision on the pledge could anger either of those groups.
Candidates have until Aug. 1 to determine whether to sign the pledge, just in time for the campaign-intensive Iowa State Fair and heavily-scrutinized Ames Straw Poll.