Nobody projects confidence like President Donald Trump, who won while promising to take America in a bold new direction by almost sheer force of will.

More than a month after taking office, though, no one seems to know exactly what direction he means. On three critical parts of his agenda — health care, tax reform and infrastructure — Trump has given limited or contradictory directions about what he expects Congress to do.

That puts pressure on the White House to fill in the blanks in his address to Congress Tuesday night, which is traditionally a platform for laying out the president's policy wish list.

“I don’t think you can do big reforms without White House leadership and air cover,” Douglas Holtz-Eakin, an economist and longtime adviser to Republican leaders, told NBC News. “They have to establish priorities.”

During the campaign, Trump’s ambiguity was an asset. He frequently shifted his stance on policy, often without acknowledging any change at all, which left voters free to choose the answer that suited them and dismiss the rest as a bluff. Would Trump pay down the entire $19 trillion national debt in “a period of eight years?” Or did he think it was “a time to borrow and borrow long term” to boost military and infrastructure spending? Take your pick: He made both statements within three weeks of each other.

But that only works as long as you never have to make a final decision that disappoints one side. Now that he’s won, Trump's bill is starting to come due.

The most immediate concern is health care. Trump made big promises before and after the election: “Insurance for everybody,” “much lower deductibles,” and zero cuts to Medicaid, the entitlement program for low-income Americans that the Affordable Care Act expanded.

What’s happened so far? After initial talk of a rapid-fire repeal bill, House Republicans are gradually cobbling together a replacement plan that would likely cover fewer people than the Affordable Care Act, promote higher deductibles as a way to lower medical costs, and reduce Medicaid spending -- all without a peep from Trump.

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The Senate is moving at a slower pace, and some members are uniting behind a dramatically different plan that would preserve Obamacare in states that want it and provide broad catastrophic coverage elsewhere.

Moderates are worried a Republican plan will leave too many people uncovered, conservatives are fearful it will be too expensive, and both sides are under pressure from an emerging anti-repeal movement filling up town halls. But we still don’t know what Trump, who has offered little guidance beyond buzzwords about health savings accounts and purchasing insurance across state lines, wants lawmakers to do in the face of these challenges.

“All of his actions and statements up to now have tended to err on the side of being vague or able to (be) read from several directions,” said Thomas Miller, a conservative health care expert at the American Enterprise Institute. ”I don’t think they’re there yet.”

Related: Trump's budget plan boosts defense, cuts safety net

Trump, who championed the repeal and replacement of Obamacare, has mentioned an impending health care plan coming in March, but it’s not entirely clear if he’s referring to a bill in Congress or a framework from his own White House.

“We have come up with a solution that’s really, really, I think, very good,” Trump told reporters Monday. “I have to tell you, it’s an unbelievably complex subject. Nobody really knew that healthcare could be so complicated.”

The same dynamic is under way on corporate tax reform, where Republicans are bogged down in a fight over whether to cut tax rates by adding a new border-adjustment tax that would reward companies that export products over those that import them. Speaker Paul Ryan is pushing hard for the border adjustment approach, but faces a high-stakes lobbying war between import-heavy retailers like Wal-Mart and Nike, who oppose the idea, and manufacturing-heavy exporters like Boeing and General Electric, who want it passed.

There’s no obvious “Republican” position to settle the dispute between competing industry groups, meaning it’s up to the president to get involved. But there’s no obvious White House position either: In January, Trump sounded skeptical of the plan (“Anytime I hear border adjustment, I don’t love it”), in February he seemed to embrace it (“It could lead to a lot more jobs”). No one can be sure what March will bring.

Treasury Secretary Steve Mnuchin sounded reluctant to come down on either side in an interview with Fox Business News on Monday.

“This is something we are studying very carefully,” Mnuchin said. “There’s certain aspects that the president likes about the concept of a border adjusted tax; there are certain aspects that he’s very concerned about.”

In both cases, Republicans will need to use budget reconciliation -- a legislative procedure that requires only a bare-majority vote in the Senate -- to pass their bills. But it’s a tricky method that adds even more pressure to stay on schedule and Republicans will confront new procedural headaches if the health care debate drags on that could affect tax reform as well.

Trump’s infrastructure plan, which adviser Stephen Bannon has said could be as large as $1 trillion, is another centerpiece of the president’s agenda but there’s even less visible movement there. Trump hinted that might change in his speech.

"I'm going to have a big statement tomorrow night on infrastructure," Trump said at a meeting with governors on Monday. "We spend $6 trillion in the Middle East and we have potholes all over our highways and our roads ... so we're going to take care of that.”

Republicans are skeptical of major federal spending projects, especially without cuts elsewhere, which means Trump will likely need to invest more political capital to keep members in line. Washington Post reporter Phil Rucker tweeted that when he asked Press Secretary Sean Spicer how the White House would pay for its plan, he received a text from a House GOP leader asking the same question.

Trump’s budget math is already running into reality. On Monday, the White House announced it would put out a budget outline that included a request for $54 billion in additional defense spending offset by unspecified cuts to discretionary spending elsewhere, which could include safety-net programs and State Department funding. So far, the White House has still not outlined the costs of its preferred infrastructure plan.

Trump’s budget prompted grumbling from fiscal conservatives, who argue there’s only limited discretionary spending available to cut and that entitlement spending needs to go down to achieve balance. Trump, however, has promised not to cut Social Security, Medicare or Medicaid. Democrats, meanwhile, argued Trump’s plan sold out his blue-collar base by reducing social spending.

White House budgets are more about messaging and it’s unlikely Trump’s will be fully enacted. But he can't put off the hard questions for much longer. And the president who promised a bigger military, a lengthy border wall, a sweeping infrastructure plan, massive tax breaks, near-universal health care, zero entitlement cuts, and a balanced budget might find the answers are less simple than he thought.