In late February, the White House asked Congress for $1.9 billion in emergency money to stem the spread of the mosquito-borne Zika virus, which at the time had been tentatively linked to birth defects in South America. Since then, the Centers for Disease Control and Prevention has concluded that the virus does cause birth defects, including microcephaly. More than 2,600 people in American states and territories have been diagnosed with Zika. As of June 16, federal health officials were tracking 481 cases of pregnant women who appeared to be infected.

Now, with mosquito season upon us, and despite evidence that a potentially calamitous health crisis could be around the corner, Congress has yet to provide money for a serious response. Indeed, some Republicans initially dismissed the threat and irresponsibly suggested that the government simply repurpose funds already earmarked to combat Ebola.

The House approved $1.1 billion in Zika funding, but with restrictions that Senate Democrats found deeply objectionable. Under the bill, only public health departments and Medicaid-run clinics would receive Zika funds to provide contraception and maternal care. Private health centers, including Planned Parenthood, would be ineligible.

That would create significant barriers to services for women in Puerto Rico, where the virus is spreading most quickly. Only 12 of the island's 78 municipalities include a Medicaid-run clinic. The same problem would limit access to care in Southern states, which are expected to be affected.

On Tuesday, Sen. John Cornyn of Texas denied that the House had intended to prevent Zika money from going to Planned Parenthood, which Republicans have sought to undermine for years. He challenged anyone to find the words "Planned Parenthood" in the explanatory text that accompanied the House bill. The words do not, in fact, appear, but the intent of the restrictions is perfectly clear, and also reckless. So far this year, four babies have been born with Zika-related defects in the U.S. That number could grow sharply in the coming months.

Given the urgency of the matter, it is not asking too much of House Speaker Paul Ryan and the Senate majority leader, Mitch McConnell, to agree on a generous bill without unjustifiable restrictions.

FROM AN EDITORIAL IN THE NEW YORK TIMES