WASHINGTON >> President Donald Trump had some blunt advice for Sen. Ron Johnson, R-Wis., who had been publicly excoriating Trump’s signature tax and spending bill as a deficit-driving debacle, at a tense White House meeting this month.

Be nice, the president told the businessperson-turned-ultraconservative politician.

Johnson immediately toned down his vocal drumbeat of criticism against the plan. But he still looms as a significant obstacle to the sweeping domestic policy bill that Senate Republicans hope to push through next week.

Not only does he declare himself adamantly opposed to the current version; he is simultaneously undercutting the party’s message that the legislation will not pile on to federal deficits.

He is, however, trying to be nicer about it.

“I’m a pretty flexible, reasonable guy,” the sometimes disputatious, three-term Republican referred to on Capitol Hill as “RonJohn” told reporters Wednesday, drawing scoffs of disbelief. “I am!”

Johnson put his accounting background to work in a dense, 30-page report he released this week that rejects claims by the administration and Republican leaders that the combination of continued tax cuts, spending reductions in the range of $1.5 trillion over 10 years and new policies will spur growth to offset lost tax revenue.

Under almost any scenario, his report says, deficits will continue to soar above $2 trillion per year, for a cumulative $20 trillion or more over the 10-year life span of the bill.

That is in line with — though substantially more favorable than — estimates by the nonpartisan Congressional Budget Office and fiscal research groups that have found that the costs of the bill would swamp any growth it could create.

“Although economic growth is an essential element to returning to fiscal sanity, without primarily focusing on the spending problem we have no hope of bringing deficits down to a manageable level,” his report states.

Johnson said he was not trying to be obstreperous and that he wanted the president, his party and its legislation to succeed. But he compared his colleagues with hopeless addicts who just can’t kick the spending habit and need him to step in and conduct an intervention.

“You have to admit you have a problem. You have to properly define it, try to look at the root causes,” he advised. “It starts there, and we haven’t done that yet.”

Since his election in 2010 as a political novice, Johnson has been a core member of a small but expanding group of far-right Senate Republicans who have clashed with their colleagues and Sen. Mitch McConnell of Kentucky, the former Republican leader.

Johnson has eagerly embraced conspiracy theories on subjects such as the 9/11 attacks and challenged the 2020 election results, while often making clear his disdain for how government works and the unwillingness of other Republicans to act aggressively to rein it in.

“Mr. Smith goes to Washington very mad,” Sen. Lindsey Graham, R-S.C., said when asked to describe Johnson, who serves on the Budget Committee, which Graham leads.

Like other colleagues, Graham said he believed Johnson was on the level with his push to reset the federal budget. Sen. Peter Welch, D-Vt., who has tried to work with Johnson, said he shared Johnson’s fear about the existential threat posed by the escalating debt, though they differ on how they would attack it.

“It is all cutting for him,” Welch said, “but I think he has a legitimate and sincere concern about the debt, and that’s why I talked to him.”

The issue, Graham and other Republicans say, is that Johnson must recognize that the legislation ultimately needs to pass both chambers of Congress, where their party holds exceptionally small majorities, and that embracing the depth of cuts that Johnson and his allies envision would make that unlikely.

“He has moved the needle his way,” Graham said, “but politics is still the art of gathering votes.”

But Johnson said his party was focused on the wrong numbers — the 218 and 51 votes needed to pass the legislation in the House and Senate, rather than the dire debt forecasts.

Republicans can only afford to lose three votes, given their 53-47 majority and solid Democratic opposition. Sen. Rand Paul, R-Ky., is already considered a hard “no” since he has said he will not support any increase in the federal debt limit, which would be raised by $5 trillion under the bill.

Sen. John Thune, R-S.D., the majority leader, said he remained optimistic about rounding up the votes despite the loud objections from Johnson and others.

“We continue to hear from our members specifically on components or pieces of the bill that they would like to see modified or changed or have concerns about, and we’re working through that,” Thune told reporters this week.

In order to win his vote, Johnson said that at minimum, he wanted assurances that Republicans would consider a second bill under the same filibuster-proof process being used this time to enact deeper spending cuts and overhauling safety net programs.

He said the guarantee of a second bill could be achieved by limiting the increase in the debt ceiling in the bill, which would require Congress to revisit the issue next year, or by reducing the scope of the policy provisions as leverage for a second bill.

Without such a commitment, he insisted he was a no. But he said he had taken to heart Trump’s admonition to be nicer.

“I think that was a legitimate point to be made,” he conceded. “I’m not always the most uplifting character.”