A large majority of Americans want honest elections, and as a result, voter ID consistently polls at 75% or 80% approval. The SAVE Act requires proof of citizenship to register, which is actually something different. Perhaps that why it is a little less popular than generic voter ID proposals, or perhaps it is the campaign that Democrats have waged against it.
Nevertheless, a strong majority of Americans favor the SAVE Act. Rasmussen finds:
The latest Rasmussen Reports national telephone and online survey finds that 63% of Likely U.S. Voters support the SAVE Act, including 47% who Strongly Support the legislation. Thirty-two percent (32%) are opposed to the bill, including 21% who Strongly Oppose the bill.
It is notable that strong support outnumbers strong opposition by more than two to one. The SAVE Act is supported by an overwhelming majority of Republicans and 60% of independents, and 43% of Democrats also buck their party elders by favoring proof of citizenship.
Election integrity is a great issue for Republicans, but only if they occasionally deliver it.
