"I want to see changes to the tax cut bill that ensure main street businesses are not put at a competitive disadvantage against large corporations," said Sen. Steve Daines (R-MT), who along with Johnson was also pressing for the same type of pass through changes.
But others in the Senate were ready to sign on, despite making earlier noise about possibly opposing the tax bill.
"I plan to vote for this bill as it stands right now. I urge my colleagues to do the same," wrote Sen. Rand Paul (R-KY) in an opinion piece on the website of Fox News.
In a new review of the Senate's version of tax reform, Capitol Hill number crunchers said - on average - the plan would lower taxes for every income level; that was different than the same review from last week, which indicated tax increases for many at lower income levels.
The change - which produced the graphic below - occurred because of a different review, leaving out the impact of the plan to end the individual mandate in the Obama health law.
The Congressional Budget Office - and other experts - argue the end to the mandate would cause other impacts for those in lower income groups, like increased health care premiums.
The Senate Budget Committee was set to meet at 2:30 pm this afternoon to vote on the package; Sen. Johnson is on that panel, and says for now he will vote 'no' unless changes are made.
That meeting will occur after the President has lunch with GOP Senators.