Table S2.
Balance check across congressional districts
| District | Control | Best | Best plus observable | Total |
| AZ 5 | 3,076 | 13,879 | 13,906 | 30,861 |
| 3.82% | 3.83% | 3.83% | 3.83% | |
| CA 11 | 2,801 | 12,459 | 12,485 | 27,745 |
| 3.48% | 3.44% | 3.44% | 3.44% | |
| FL 22 | 3,489 | 16,233 | 16,230 | 35,952 |
| 4.34% | 4.48% | 4.47% | 4.46% | |
| IA 3 | 3,325 | 14,378 | 14,354 | 32,057 |
| 4.13% | 3.97% | 3.96% | 3.98% | |
| IL 10 | 2,524 | 11,322 | 11,309 | 25,155 |
| 3.14% | 3.12% | 3.12% | 3.12% | |
| IL 14 | 2,374 | 10,808 | 10,807 | 23,989 |
| 2.95% | 2.98% | 2.98% | 2.98% | |
| IL 17 | 2,339 | 10,713 | 10,744 | 23,796 |
| 2.91% | 2.95% | 2.96% | 2.95% | |
| IN 9 | 3,204 | 14,767 | 14,762 | 32,733 |
| 3.98% | 4.07% | 4.07% | 4.06% | |
| MA 10 | 3,506 | 15,642 | 15,662 | 34,810 |
| 4.36% | 4.31% | 4.32% | 4.32% | |
| MD 1 | 3,221 | 14,424 | 14,427 | 32,072 |
| 4.00% | 3.98% | 3.98% | 3.98% | |
| MI 7 | 2,349 | 10,244 | 10,247 | 22,840 |
| 2.92% | 2.83% | 2.83% | 2.83% | |
| MI 9 | 2,841 | 12,955 | 12,965 | 28,761 |
| 3.53% | 3.57% | 3.57% | 3.57% | |
| MN 1 | 3,662 | 16,599 | 16,622 | 36,883 |
| 4.55% | 4.58% | 4.58% | 4.58% | |
| NC 8 | 3,418 | 15,713 | 15,717 | 34,848 |
| 4.25% | 4.33% | 4.33% | 4.32% | |
| ND 1 | 1,294 | 5,805 | 5,783 | 12,882 |
| 1.61% | 1.60% | 1.59% | 1.60% | |
| NY 19 | 2,877 | 12,982 | 12,978 | 28,837 |
| 3.58% | 3.58% | 3.58% | 3.58% | |
| NY 23 | 1,699 | 7,835 | 7,827 | 17,361 |
| 2.11% | 2.16% | 2.16% | 2.15% | |
| NY 24 | 2,888 | 13,361 | 13,374 | 29,623 |
| 3.59% | 3.69% | 3.69% | 3.68% | |
| OH 15 | 4,235 | 19,019 | 19,035 | 42,289 |
| 5.26% | 5.25% | 5.25% | 5.25% | |
| OH 18 | 3,485 | 15,735 | 15,770 | 34,990 |
| 4.33% | 4.34% | 4.35% | 4.34% | |
| PA 10 | 2,932 | 13,307 | 13,304 | 29,543 |
| 3.64% | 3.67% | 3.67% | 3.67% | |
| PA 11 | 1,782 | 8,123 | 8,113 | 18,018 |
| 2.21% | 2.24% | 2.24% | 2.24% | |
| PA 12 | 1,676 | 7,378 | 7,372 | 16,426 |
| 2.08% | 2.03% | 2.03% | 2.04% | |
| PA 15 | 2,258 | 9,797 | 9,802 | 21,857 |
| 2.81% | 2.70% | 2.70% | 2.71% | |
| PA 3 | 2,068 | 9,461 | 9,473 | 21,002 |
| 2.57% | 2.61% | 2.61% | 2.61% | |
| PA 7 | 2,941 | 12,926 | 12,930 | 28,797 |
| 3.65% | 3.57% | 3.56% | 3.57% | |
| SD 1 | 3,192 | 14,325 | 14,317 | 31,834 |
| 3.97% | 3.95% | 3.95% | 3.95% | |
| WI 7 | 2,761 | 12,474 | 12,476 | 27,711 |
| 3.43% | 3.44% | 3.44% | 3.44% | |
| WI 8 | 2,252 | 9,907 | 9,925 | 22,084 |
| 2.80% | 2.73% | 2.74% | 2.74% | |
| Did not vote in 2008 | 16,048 | 72,314 | 72,359 | 160,721 |
| 19.94% | 19.94% | 19.95% | 19.95% | |
| Voted in 2008 | 64,421 | 290,257 | 290,357 | 645,035 |
| 80.06% | 80.06% | 80.05% | 80.05% | |
| Total | 80,469 | 362,571 | 362,716 | 805,756 |
LR chi2(58) = 25.91; Pr = 1.000.