Two groups opposed to an Internet sales tax are touting a poll that shows members who support it could be punished by voters. 

The poll conducted for the National Taxpayers Union and the R Street Institute finds 57 percent of voters oppose the plan to allow states to collect a sales tax on Internet purchases from wholesalers with no physical presence in their states. Just 35 percent approve of the idea.

That number falls even lower with Republicans: Two thirds oppose the plan, while just 27 percent support it.

The numbers could spell trouble for Sen. Mike EnziMike EnziTrump should work with Congress to block regulations on prepaid cards GOP wrestles with big question: What now? Top Dem: Trump's State Dept. cuts a 'Ponzi scheme' MORE (R-Wyo.), the leading advocate of the plan in the Senate who is facing a primary challenge from Liz Cheney (R). 

It could also become a campaign issue for red-state Democrats like Sens. Mark BegichMark BegichPerez creates advisory team for DNC transition The future of the Arctic 2016’s battle for the Senate: A shifting map MORE (Alaska), Kay HaganKay HaganLinking repatriation to job creation Former Sen. Kay Hagan in ICU after being rushed to hospital GOP senator floats retiring over gridlock MORE (N.C.), Mary LandrieuMary LandrieuMedicaid rollback looms for GOP senators in 2020 Five unanswered questions after Trump's upset victory Pavlich: O’Keefe a true journalist MORE (La.) and Mark PryorMark PryorMedicaid rollback looms for GOP senators in 2020 Cotton pitches anti-Democrat message to SC delegation Ex-Sen. Kay Hagan joins lobby firm MORE (Ark.).

The proposal passed the Senate earlier this year, but was dead on arrival in the GOP-controlled House.

The poll of 1,000 likely voters was conducted from Sept. 10-11 and has a margin of error of plus or minus 3.1 percentage points.