Bush: Unapologetic proponent of Common Core education standards and immigration changes opposed by many in GOP.
Christie: Moderate on the reach and functions of government; bipartisanship.
Cruz: Anti-Obama's health care law, pushes broader tea party agenda.
Jindal: A record of privatization to show he means government should be trimmed, happy to carry a social conservative banner.
Paul: Tea-party plus, with a libertarian streak that places him to the left of rivals on some issues, to the right on others. Fiscal conservative, criticizes surveillance state. Says GOP should back off on pushing state voter ID laws offensive to blacks. Health law scold. Joining in 2014 with liberal lawmakers and others in effort to roll back some mandatory minimum sentences and give judges more flexibility in fitting punishment to crime.
Perry: Prominent voice on conservative issues since before the birth of the tea party. Wants to ban all abortion in Texas, relax environmental regulations, boost states' rights; opposes gay marriage.
Rubio: 2014 initiative on poverty calls for federal wage supplements for some low-wage workers instead of earned income tax credit. Economy, abortion, tea party fiscal conservatism; immigration liberalization if he decides to get back to it. Another voice against health care law. Has become a leading GOP voice in foreign policy, pressing for stronger U.S. action in geopolitical hot spots. On climate change: "I do not believe that human activity is causing these dramatic changes to our climate the way these scientists are portraying it."
Ryan: Cutting spending, taking on entitlements, rolling back Obama's health law. Anti-poverty initiative this year.
Santorum: Social conservative activism goes way back. Focus on blue-collar economic opportunity. Speaking against libertarian streak in GOP, a "strain of conservatism that has no basis in conservatism." Book calls climate change "hyped-up crisis."