Suddenly, President Donald Trump's legislative agenda is in deep trouble.

On health care, the budget and tax reform, Trump faces strong resistance barely a month into his presidency. Though Republicans who control Congress have set a streamlined path designed to make Democrats irrelevant, disagreements within the GOP now threaten that plan across the board.

The plan calls for repealing Obamacare and replacing it by mid-April, passing a fiscal 2018 budget and then enacting tax reform by August. That ambitious timetable sounds reasonable in light of recent history; by the end of February 2009, under new President Barack Obama, Democratic congressional majorities had already swept through a massive economic stimulus.

But neither the White House nor congressional Republicans have yet released their long-promised plans to replace Obamacare with better, cheaper alternatives. On Monday, leaders of two different conservative groups within the House Republican caucus declared their opposition to the approach advanced by Speaker Paul Ryan.

Their objection: the plan's tax credits for Americans to buy insurance represent a new federal entitlement too much like Obamacare itself. Yet such tax credits are vital to preventing massive drops in the number of people with health insurance, which Senate Republicans, Republican governors and Trump himself have said they want to avoid.

Ryan aims to overcome intraparty resistance by daring GOP dissenters to vote no when a repeal-and-replacement plan reaches the House floor. That's a risky approach to take with firebrands so willing to defy their leaders that they forced the resignation of the speaker's predecessor, John Boehner.

The White House on Monday outlined its broad approach for the budget. Budget Director Mick Mulvaney said the administration aimed to boost defense spending by $54 billion, financed through offsetting cuts in domestic spending.

His objective faces huge obstacles. Such a budget shift would require legislation to alter statutory spending caps that, unlike the Obamacare repeal Trump hopes to pass, would not be shielded from Senate filibuster.

Chances the White House could attract the eight Democrats needed to back such a shift are remote. So are chances of holding all 52 Senate Republicans behind it.