| It doesn't stop|
at the water's edge
Wedge issues in politics are generally issues on which people have strong opinions that can be "owned" as part of a political base. In modern-day America, most of these are social issues with religious overtones, such as abortion and homosexuality. Other favorites include gun control, being "tough on crime", and militarism.
They are phrased or argued in such a way that the opposing viewpoint, if there is one, can be easily labeled in a derogatory manner, thus creating a false dilemma. Resulting examples would include being "soft on crime," "weakening America" (or "emboldening our enemies"), "against family values," "coming to take your guns away," etc.