One of the health care bills under consideration by Republican leaders would take health insurance away from 32 million people over the next decade, creating a cohort of Americans who could be motivated to vote against senators who approved the measure.

The Senate could vote as early as Tuesday, but it is not yet clear which of the two bills in contention that the majority leader, Mitch McConnell, intends to bring up. The plan that would leave 32 million without coverage would repeal some of the most important parts of the Affordable Care Act without any replacement.

If they pass the bill, some Republicans might put themselves in a difficult situation because many of them won their last election by fewer votes than the number of people who would lose health coverage in their state under the proposed legislation. The comparison shows the scale of the problem some Republicans might face in close races in 2018 and 2020.

Margin of victory in last election Newly uninsured by 2019 Republican senators Up for re-election in 2018 or in 2020 0 500,000 1 million 1.5 million 2.0 million 2.5 million Marco Rubio FLA. Ted Cruz TEX. John Cornyn TEX. Thom Tillis N.C. Patrick J. Toomey Pa. David Perdue GA. Richard M. Burr N.C. Jeff Flake ARIZ. Cory Gardner Colo. Johnny Isakson GA. Roy Blunt MO. Bill Cassidy LA. John McCain ARIZ. John Kennedy LA. Dean Heller NEV. Ron Johnson WIS. Todd Young IND. Mitch McConnell Ky. Tom Cotton ARK. Rand Paul Ky. Lindsey Graham S.C. Joni Ernst IOWA Pat Roberts KAN. Lamar Alexander TENN. John Boozman ARK. Thad Cochran MISS. Steve Daines MONT. Shelley Moore Capito W.VA. Dan Sullivan ALASKA Jim Risch IDAHO Deb Fischer NEB. Roger Wicker MISS. Mike Rounds S.D. Lisa Murkowski ALASKA Note: Excludes senators where the margin of victory is greater than the number of uninsured. Margin of victory in last election Newly uninsured by 2019 Republican senators Up for re-election in 2018 or in 2020 1 million 2.0 million 0 Marco Rubio FLA. Ted Cruz TEX. John Cornyn TEX. Thom Tillis N.C. Patrick J. Toomey pa. David Perdue GA. Richard M. Burr N.C. Jeff Flake ARIZ. Cory Gardner colo. Johnny Isakson GA. Roy Blunt MO. Bill Cassidy LA. John McCain ARIZ. John Kennedy LA. Dean Heller NEV. Ron Johnson WIS. Todd Young IND. Mitch McConnell Ky. Tom Cotton ARK. Rand Paul Ky. Lindsey Graham S.C. Joni Ernst IOWA Pat Roberts KAN. Lamar Alexander TENN. John Boozman ARK. Thad Cochran MISS. Steve Daines MONT. Shelley Moore Capito W.VA. Dan Sullivan ALASKA Jim Risch IDAHO Deb Fischer NEB. Roger Wicker MISS. Mike Rounds S.D. Lisa Murkowski ALASKA Note: Excludes senators where the margin of victory is greater than the number of uninsured. Margin of victory in last election Newly uninsured by 2019 Republican senators Up for re-election in 2018 or in 2020 0 500,000 1 million 1.5 million 2.0 million 2.5 million Marco Rubio FLA. Ted Cruz TEX. John Cornyn TEX. Thom Tillis N.C. Patrick J. Toomey Pa. David Perdue GA. Richard M. Burr N.C. Jeff Flake ARIZ. Cory Gardner Colo. Johnny Isakson GA. Roy Blunt MO. Bill Cassidy LA. John McCain ARIZ. John Kennedy LA. Dean Heller NEV. Ron Johnson WIS. Todd Young IND. Mitch McConnell Ky. Tom Cotton ARK. Rand Paul Ky. Lindsey Graham S.C. Joni Ernst IOWA Pat Roberts KAN. Lamar Alexander TENN. John Boozman ARK. Thad Cochran MISS. Steve Daines MONT. Shelley Moore Capito W.VA. Dan Sullivan ALASKA Jim Risch IDAHO Deb Fischer NEB. Roger Wicker MISS. Mike Rounds S.D. Lisa Murkowski ALASKA Note: Excludes senators where the margin of victory is greater than the number of uninsured.

Of course, not everyone who faces a tougher insurance market will be swayed to vote against incumbent Republican senators who backed the bill, if only because voters won’t see the effects immediately. Under the repeal without replacement bill, Obamacare’s expanded Medicaid coverage would end in 2020, after the 2018 midterm election. Under the other Senate bill under consideration, the Better Care Reconciliation Act, big cuts to Medicaid would start in 2021, the year after the next presidential election.

Still, many voters might be worried about the prospect of losing coverage, or entering an insurance market that no longer has the protections of the Affordable Care Act, as they cast their votes next year and in 2020.

Among Republican senators, 31 are running for re-election in 2018 and 2020.

Of those, 22 are running in races where the number of uninsured under the repeal without replacement bill would be greater than the margin of victory in their last election, a sign that voters affected by the Republican health plan could possibly sway the outcome against them.

Low Turnout May Help Republicans

Many Republicans who are up for re-election and support the repeal bill are surely counting on people upset about this legislation to not show up to vote, or to vote for them regardless.

That might be a reasonable political calculation because low-income Americans, who would be among the most hurt by the destruction of the A.C.A., tend to vote at lower rates than more affluent families.

But Republican senators ought to remember that older Americans, for whom this bill would also have devastating effects, tend to vote at higher rates than younger people. In the last presidential election, many of these voters broke for Donald Trump, but they might be less inclined to back Republican candidates once this bill becomes law.

Election turnout 80.2 By annual income By age 76.9 73.8 71.4 68 66.2 63 58.4 56.9 55.8 50.4 46.9% 45.8 43.4% 100k - 149k 10k - 14k 15k - 19k 20k - 29k 30k - 39k 40k - 49k 50k - 79k 75k - 99k 150k+ 18 - 29 30 - 44 45 - 59 60+ <10k Note: Data for 2012. Source: Demos.org Note: Data for 2016 Source: ElectProject.org Election turnout By annual income 46.9% <10k 10k - 14k 45.8 50.4 15k - 19k 20k - 29k 55.8 30k - 39k 58.4 40k - 49k 63 50k - 79k 68 75k - 99k 73.8 100k - 149k 76.9 150k+ 80.2 Note: Data for 2012. Source: Demos.org By age 43.4% 18 - 29 18 - 29 56.9 30 - 44 66.2 45 - 59 71.4 60+ Note: Data for 2016. Source: ElectProject.org

The Senate repeal without replacement bill would cut Medicaid spending by $842 billion over 10 years compared to current law, according to the Congressional Budget Office.

Nearly two-thirds of Americans are opposed to such drastic cuts, including the vast majority of Democrats and a solid majority of independents, according to a Kaiser Family Foundation poll. But about 54 percent of Republican voters support big cuts to the program, which may help explain why some lawmakers from the party are ambivalent about or hostile toward the program.