To hear hard-liners tell it, this nation’s immigration problem boils down to one issue: border security. Fix it, and everything else will fall into place. In reality, if they were to divert every dollar in President Barack Obama’s proposed $4 trillion budget for border security, America’s immigration problem would remain only half-solved.

Increased border security helps deter new migrants from entering and helps boost the number of apprehensions of those who do cross, such as the tens of thousands who surrendered at the border last summer. Yes, tighter border security helped ensure those crossers were captured immediately.

Once in U.S. custody, though, they join the hundreds of thousands already awaiting court hearings to determine whether they merit deportation. An appalling backlog in the nation’s immigration courts is why border security alone can’t solve the problem. Thousands of unauthorized migrants are being told they must wait until 2019 before their day in court arrives.

The backlog is one that Congress has failed repeatedly to address, regardless of which party is in control. With the GOP now controlling both houses of Congress, Republicans can no longer avoid the court problem.

Emphasis on border security has led to a tripling in staffing by the U.S. Border Patrol since 1997. There’s been a corresponding surge in the backlog faced by U.S. immigration courts because, while it might take only a few minutes to catch a border crosser, it can take an average of more than 800 days to process that migrant through the courts. There are only around 230 judges to handle the nearly 430,000 cases pending.

The frenzy of allocations in last fall’s federal spending bill to build detention centers and bolster border security didn’t include similar increases in funding to hire more immigration court judges. If apprehensions at the border continue to rise, the backlog seems destined to go from bad to worse.

Congress must not confuse funding for immigration courts with the threatened withholding of Homeland Security Department funds to punish the president for his unilateral action to protect millions of immigrants from deportation. Immigration courts are under Justice Department jurisdiction. The only way to ensure the speedy processing of those unauthorized immigrants already here is to give the courts the resources they need.

Members of Congress who insist on tougher security to cut the numbers of unauthorized immigrants in this country must give the law a chance to work. Adequate court funding is the only way to clear this horrendous backlog.