Senate Majority Leader Mitch McConnell, R-Ky., and other Republicans ended the year in a mood of undeserved triumph, congratulating themselves for passing a big — and fiscally dangerous — tax bill. They also began teeing up an agenda for 2018. Will the GOP-majority Congress continue trying to govern on behalf of the third of the country furthest to the right, or will leaders chart a better direction?

A constructive course could reflect many of the priorities McConnell identified. Top on the list should be providing protections for “dreamers,” undocumented immigrants brought to this country as children who are otherwise fully integrated into American society. President Donald Trump set their current, semi-protected status to lapse starting in March. Though their new tax bill will make it much harder to fund federal operations, lawmakers must also prevent mandatory budget caps from harming military readiness and domestic programs even more than they already have, and they should seek to invest more money in the nation’s roads and rails.

For his part, Trump has put an infrastructure bill on his wish list for this year. If congressional leaders finally allowed an up-or-down vote on items such as these, some would pass easily. Congress also must pursue its probe of Russian meddling in U.S. elections and stand ready to protect the special counsel’s investigation from political interference.

Other GOP leaders have signaled a less productive approach. House Speaker Paul Ryan, R-Wis., has been making the case for curbing entitlements — expensive federal programs that automatically draw money from the treasury every year. Entitlements do need to be trimmed in order to check the national debt. But Republicans appearfocused on cutting programs that help the poor, such as food stamps and Medicaid, rather than ambitiously reforming Medicare and Social Security, the far larger middle-class entitlements that really drive long-term debt.

After just handing wealthy Americans a massive tax cut, Republicans would be cruel indeed to cite the deficit as pretext for eroding the social safety net on which the poorest depend, particularly as they preserved benefits for richer people. This would also be yet another entirely party-line effort.

Similarly, Sen. Lindsey Graham, R-S.C., insisted that Republicans must try again to repeal and replace Obamacare, presumably by reconsidering an unappealing plan he failed to shepherd through the Senate in 2017. In fact, Republicans in their tax bill just repealed an important piece of Obamacare. The priority now must be minimizing the fallout. That starts with passing two stabilization bills that relatively moderate Republicans have negotiated with Democrats. Unless Republicans want to be responsible for a health-care disaster, they will need to act swiftly.

When asked about entitlements and Obamacare repeal, McConnell carefully avoided substantial commitments to pursue the no-compromise GOP agenda to which others in the party still cling. The rest of Congress should follow that lead.

Editorial by The Washington Post