Hillary Rodham Clinton's backup plan if she falters in Iowa can be summed up in two words: New Hampshire. Clinton's Democratic team is preparing television ads here criticizing Barack Obama's health care plan and working to build what campaigns call a firewall. If the Obama presidential campaign ignites in Iowa, she wants to be ready to cool him off in a state where her organization is strong and her support has proven durable. The Iowa and New Hampshire primaries are the first in the run up to the presidential election and the results have been known to make or break candidates. This past weekend, the Clinton campaign already had volunteers going door-to-door with fliers criticizing Obama on health care. Possible TV ads to run against him also have been previewed in the state.