Demographic trends could compound the political challenges Democrats face in their struggle to assemble a majority for health care reform in the House of Representatives. As the following tables show, about two-thirds of the roughly 100 Democratic House members who are not considered firm supporters of the legislation represent districts where senior citizens represent a larger share of the population than they do nationally (12.6 percent); in polls many seniors have expressed concern that the reform package will hurt Medicare.

On the other hand, only about 40 of the target Democrats represent districts where the share of residents without health insurance exceeds the national average of 15 percent. These figures on access to insurance are drawn from the Census Bureau's 2008 American Community Survey, which produced a slightly different overall rate of insurance coverage for the nation than the bureau's annual report on health insurance. That report uses another survey (the Annual Social and Economic Supplement to the Current Population Survey) to calculate its figures. The annual report placed the share of Americans without health insurance at 15.4 percent; the ACS put it at 15 percent. The district level and national figures on the senior population are drawn from a three-year average of the American Community Survey that the Census Bureau publishes.

When the House initially passed the health care bill last November, 39 Democrats voted no. Of those, 17 represent districts where the share of residents without health insurance exceeds the national average. Four no votes -- Chet Edwards of Texas, Dan Boren of Oklahoma, Harry Teague of New Mexico, and Mike McIntyre of North Carolina -- represent districts where at least 20 percent of residents lacked health insurance. All four are currently expected to vote no again when the final bill reaches the floor.

Meanwhile, of the initial 39 no votes, 25 represent districts where seniors exceed their national share of the population. These members include some of the leadership's top targets in the final scramble for votes, including Pennsylvania's Jason Altmire and John Adler of New Jersey.

The tables that follow group target Democrats by their votes on the health care bill that cleared the House last November, as well as their position on the amendment from Rep. Bart Stupak, D-Mich., to restrict federal funding of abortion in health benefits provided through the legislation. For each Democrat, the table lists whether Barack Obama or John McCain carried their district in 2008; the share of their population that is uninsured or over 65, and the latest assessment of their position on the bill. National Journal will continue to update the lists as the vote approaches.

Dem Targets: No On Reform, No On Stupak


Dem Longshots: No On Reform, Yes On Stupak


GOP Targets: Yes On Reform, Yes On Stupak


GOP Longshots: Yes On Reform, No On Stupak


--National Journal researcher Cameron Joseph contributed to this report