No one knows exactly when the first Aedes aegypti mosquito will transmit the Zika virus inside the U.S., but it might happen before lawmakers manage to pass a bill to pay for its prevention and control.

Last week, Senate Democrats blocked a Republican plan to partly fund President Obama’s request – issued over four months ago – for money to fight Zika. The White House had asked for almost $1.9 billion to help states control mosquitoes, create faster tests for the virus and develop a vaccine, among other things. Congressional Republicans offered $1.1 billion, with strings attached.

One of them was that none of the money go to women’s health clinics such as those run by Planned Parenthood. That’s nonsensical, since Zika can be sexually transmitted, and its worst effects can be prevented with birth control. Republicans also proposed other dubious conditions, such as loosening Clean Water Act restrictions on some pesticides and cutting the budget for Obamacare.

Naturally, the partisans disagree over which side is more heartless in its disregard for pregnant women and their babies at risk of developing Zika-related microcephaly. Meanwhile, as they have dithered, 265 pregnant women in the U.S. have been infected with the virus. Zika-related birth defects are believed to have been found in at least four newborns and in four lost pregnancies. And mosquitoes continue spreading the virus in dozens of other countries.

It’s possible that Congress’ latest failure is merely posturing – that lawmakers have made their partisan points and plan to approve funding for Zika when they reconvene before their summer recess. If so, it’s small comfort.