The Democratic National Committee grass-roots outfit Organizing for America is beginning a door-to-door campaign to drum up popular backing for President Barack Obama’s health care overhaul effort.An e-mail being sent to OFA members — many of whom were on Obama’s vast campaign e-mail list — instructs activists to begin canvassing door-to-door on weekends to ask neighbors to “sign on in support of the President’s agenda and call their representatives in Congress,— according to one of the e-mails being sent out.“When we all get together and organize door-by-door, block-by-block, and neighborhood-by-neighborhood, we can build a movement from coast to coast,— the e-mail states. “It’s how we won a historic election – and it’s how we’ll make real, comprehensive health care reform a reality in 2009. This debate is heating up, so it’s important that we organize now to ensure that President Obama’s core principles are included in any comprehensive health care reform legislation.— The missive warns that “over $1.4 million— is being spent daily “to block reform in the halls of Congress— and that “these next few weeks will make the difference on health care reform.—