Michele Bachmann, Rick Perry and Newt Gingrich are hoping their bus tours can form enough of a roadblock for Mitt Romney.

Bachmann, Perry and Gingrich are ready to start bus tours through Iowa Tuesday, making their final pitch as conservative alternatives to Romney. The former Massachusetts governor is set to visit with voters in New Hampshire in the morning before returning to Iowa.

Their campaigns are weighing the challenge they face from Ron Paul, the Texas congressman who has deep support among libertarians. Paul’s supporters have not really stopped organizing in the state since his 2008 bid, and he could have a better-than-expected showing in the Jan. 3 Iowa caucuses. The caucuses begin the GOP nominating calendar.

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