A day after the US Senate passed a spending bill to end the longest-ever government shutdown, the budget fight now moves to the House of Representatives.

The lower chamber of Congress is expected to vote this week on the funding measure.

Unlike in the Senate, if House Republicans stay united, they don’t need any Democrats to pass the budget. But the margin for error is razor thin.

Here are four potential hold-ups for the budget, before it can clear Congress and land on the president’s desk for signing into law.

A key sticking point throughout the shutdown has been a desire on the part of Democrats to attach to the spending bill a renewal of tax credits that make health insurance less expensive for 24 million Americans.

Senate Republicans instead only agreed to offer Democrats a vote in December on whether to extend the subsidies – something they had already offered weeks ago.

And House Speaker Mike Johnson would not commit on Monday to allowing a vote in his chamber on the tax credits.

This entails a fair degree of political risk for Republicans, however. If they torpedo the subsidies, health coverage premiums could rocket for millions of people, handing Democrats a ready-made campaign issue for next year’s midterm elections.

Marjorie Taylor Greene, a conservative Republican congresswoman from Georgia, has broken ranks with Trump to warn that her party must ensure health insurance premiums do not spike.

As the clock ticks down to the subsidies expiring by the end of December, Republicans are working out their plan.

They want income caps on who can receive the tax credits, and are proposing the tax dollars bypass insurance companies and go straight to individuals – although the details are unclear.

Out of power in Washington, where Trump’s Republicans control the House and Senate, Democrats appeared finally to have some political wind in their sails after a handful of election wins last week in Virginia, New Jersey and New York City.

But those victories, like the shutdown fight, have accentuated strategic tensions between the pragmatic and progressive, or left-wing, factions of the party.

The Democratic left is furious at defectors who voted with Senate Republicans to pass the budget on Monday, seeing this as a capitulation to President Donald Trump.

From that wing of the party, Senator Bernie Sanders of Vermont said giving up the fight was a “horrific mistake”. California Governor Gavin Newsom called it “surrender”.

Congressman Greg Casar of Texas, the chairman of the House Progressive Caucus, warned: “A deal that doesn’t reduce healthcare costs is a betrayal of millions of Americans counting on Democrats to fight for them.”

However, centrist lawmakers like Jared Golden of Maine, who represents one of the most conservative districts in the nation held by any Democrat, may cross the aisle.

Golden, who recently announced he won’t run for re-election, is likely to vote for the package, his office indicated to Axios, a political outlet, on Monday.

Another moderate Democrat, Henry Cuellar of Texas, could help get the Republicans’ spending plan over the line.

“It’s past time to put country over party and get our government working again for the American people,” he posted on social media on Sunday.

Republicans control the House, holding 219 seats against the Democrats’ 213, but can only afford to lose two votes to pass the spending plan.

While most House Republicans are expected to support the funding bill, fiscal hawks in the party will raise objections.

Thomas Massie of Kentucky has repeatedly voted against such stopgap funding extensions.

The proposed deal would leave the federal government on a path to keep adding about $1.8tn (£1.4tn) a year to its $38tn of debt.

Rand Paul of Kentucky cited this spending glut as he became the only Republican in the Senate to vote against the budget.

The Senate plan would extend funding only until January, but the conservative House Freedom Caucus is arguing for a budget that would last longer and do more to rein in government spending.

House Speaker Mike Johnson has kept the chamber out of session for the last seven weeks to focus pressure on Senate Democrats to make a shutdown deal.

Now he is urging lawmakers to start returning immediately to Washington with a vote set for Wednesday afternoon at the earliest.

But members of Congress face the same flight delays that have plagued other Americans during the spending impasse.

From Tuesday, the rate of reduction in US flights will increase to 6%. Cuts have been made as the nation’s busiest airports reduce their capacity to cope with shutdown-related sickness by air traffic controllers, who have been working without pay during the shutdown.

Record-cold temperatures and heavy snow have also hit the Great Lakes region in the Midwest, adding to the delays.