A Republican lawmaker introduced legislation Thursday to shore up Social Security's finances and boost benefits for low-income workers without raising taxes, a conservative version of reform that could gain attention under unified GOP government next year.

The bill put forward by Texas' Sam Johnson, the chairman of the subcommittee on Social Security, would reduce costs by changing the benefits formula to reduce payments progressively for high earners. It would also gradually raise the full retirement age from 67 to 69 for people who are today 49 or younger. Lastly, it would change the inflation metric used to calculate benefits to one that shows lower inflation, essentially slowing the growth in benefits, and eliminate cost of living adjustments for high earners.

On the flipside, it would increase benefits for lower-income workers, and raise the minimum benefit for low-earners who worked full careers.

Johnson called the plan the "start of a fact-based conversation" on how to fix Social Security's finances.

Social Security's trust funds for retirement and disability payments are projected to run out by 2034 if Congress doesn't take action. At that point, beneficiaries would see an immediate cut in benefits of about a fifth.

Johnson's is one version of reform to stave off that possibility. This summer, a bipartisan group of lawmakers also put forward legislation that would improve Social Security's finances in part by raising payroll taxes.

President-elect Trump has suggested that he wants to crack down on waste and fraud in Social Security, but isn't interested in a broad overhaul of the retirement program.

Congressional Democrats, meanwhile, have moved to the left on Social Security, with key lawmakers favoring an increase in benefits for some groups, rather than any reductions.

Johnson's bill won't become law in the current Congress, but his proposal could be brought up in the new Congress early next year.