An overwhelming majority of Americans favor banning members of Congress from trading stocks, but efforts to turn that public sentiment into law have long sputtered.

That's because the lawmakers who would have to approve any overhaul of congressional investing stand to suffer considerable financial impacts -- not least of which are potentially hefty tax liabilities if they are forced to sell off long-held stocks.

Now the issue is coming to a head with a new House bill that has a strange-bedfellows coalition of hardcore conservatives and good-government liberals behind it, and they are hoping they can convince their more skeptical colleagues to accept some new financial realities.

Under proposed language, lawmakers would be able to take advantage of a rare perk generally not available to the public, which would allow them to defer taxes on the sale of prohibited securities. On the flip side, they would face hefty penalties if they fail to sell off their holdings.

If passed, the bill would permanently change the financial calculations of any member or would-be lawmaker. The tax arrangement, for instance, could prove immensely useful to wealthy people who want to diversify their assets. But it could dissuade investors who have no interest in abandoning lucrative stakes for workaday mutual funds.

Proponents of the new bill say taking historic steps towards eliminating conflicts of interest for lawmakers who hold stocks is worth the upheaval. A 2023 University of Maryland poll found 86 percent of registered voters support a ban on member trading.

"Eliminating corruption, eliminating conflicts of interest, is the North Star that we have set out to accomplish," said Rep. Seth Magaziner (D-R.I.), the lead sponsor of the legislation, said in an interview Thursday.

"In order for that to work, you have to deal with the tax implications," he added. "Otherwise, not only existing members, but anyone who wants to run for Congress could face a big tax bill upon being elected."

According to the bill, which is co-led by Rep. Chip Roy (R-Texas), current members would have 180 days to divest from individual stocks, while incoming members would have 90 days to do so. It's a more aggressive approach than other proposals that would allow for blind trusts, where a member or candidate keeps their stock holdings but relinquishes control of investing decisions.

Selling stocks typically triggers at least a 15 percent tax on all the capital gains accumulated since the individual bought the stock. For wealthy Americans with longstanding holdings, that could mean forking over huge sums that could otherwise sit in their portfolios and continue to appreciate.