The linked report contains the Treasury Inspector General for Tax Administration (TIGTA) determination of the impact of the new cap on SALT deductions. Figure 2: Estimated Number of Taxpayers Subject to the SALT Limitations, and Amounts of State and Local Taxes Paid Over the SALT Limitations in Tax Year 2018 (see page 8) shows 10,880,570 affected taxpayers.
Since 7,763,869 of these taxpayers are married filing jointly that equates to 18,644,439 potential 2020 voters. Many of these voters were or will be hit with a “withholding surprise” upon filing their 2018 Federal returns. Other things being equal, these adversely affected voters are more likely than not to be hostile toward Trump and or the GOP, especially if the House Democrats pass a realistic “SALT CAP Solution” and the GOP Controlled Senate and or Tramp fails to enact this legislation.