Senate Majority Leader Mitch McConnell (R-Ky.) criticized Democrats for again blocking a Zika spending bill. (AP Photo/Evan Vucci, File)

Senate Democrats on Tuesday for the third time in two months blocked a $1.1 billion legislative package to help fight the Zika virus, but lawmakers in both parties said they now hope negotiations will begin in earnest to quickly come up with a bipartisan deal to address the potential public health crisis.

Congress is under intense pressure to pass a funding agreement before the end of September when Centers for Disease Control director Tom Frieden estimates his agency will run out of money to continue its efforts to combat the spread of Zika, which can cause birth defects. After months of bickering over the details of a deal, many in Congress expect that lawmakers now back in Washington after a seven-week break will feel a renewed urgency to find a solution this month before heading home for the elections.

“It is certainly a moral imperative for the Congress of the United States to pass legislation which will meet a very critical health challenge to its citizens,” House Minority Whip Steny Hoyer (D-Md.) told reporters Tuesday.

Before those negotiations begin in earnest, however, Senate Republicans on Tuesday were eager to make a political point by forcing Democrats to once more block Zika legislation that passed the House earlier this year.

“Today we’ll give Senate Democrats another opportunity to follow through on their own calls for action on Zika,” said Senate Majority Leader Mitch McConnell (R-Ky.) on the Senate floor.

The vote was 52 to 46 and 60 votes were needed for the legislation to advance. The Zika funding is part of a broader bill funding the Pentagon and veterans programs.

Democrats are blocking the legislation over objections to what they charge are politically-motivated provisions added to the bill by Republicans, including language preventing the Zika funds from being used by Planned Parenthood and provisions relaxing use of certain pesticides.

But there is near universal agreement in Congress that lawmakers must do something ahead of the elections to show they are taking steps to help prevent the spread of mosquito-borne virus.

The CDC reports that there were 35 cases of locally-transmitted cases of Zika in the United States as of August 31. An additional 2,686 were reported as travel-related transmissions. At least 16 babies have been born in the United States with birth defects linked to the virus.

Mosquito season typically lasts through October and transmission could continue through that time period. Frieden told reporters in July that the agency “might not have the resources” to send teams to support local and state officials if the virus spreads after the money runs out in September.

“Basically, we’re out of money, and we need Congress to act to allow us to respond effectively,” he said.

This time pressure has many, including Sen. Marco Rubio (R-Fla.), preparing to link Zika talks with negotiations to pass a short-term spending bill before the fiscal year ends on Sept. 30.

Senate Majority Whip John Cornyn (R-Texas) said Tuesday that he thinks it would make sense to combine the budget and Zika talks.

“We can’t neglect that any longer,” Cornyn said. “I think trying to find some path forward in a year-end appropriations bill would make sense.”

He said it is likely that Congress will have to pass a short-term spending bill that would keep the government open until sometime after the election in November. Cornyn said that while he would prefer to avoid reopening spending talks in November or December, it is clear Democrats and President Obama will only accept a short-term extension of current spending.

If Zika and the broader spending talks are linked, Democrats insist Republicans will likely be forced to return to a bipartisan deal the Senate approved in May. That bipartisan compromise legislation would have provided $1.1 billion in Zika funding through September 2017 and it did not include the added provisions objected to by Democrats.

The House rejected that proposal after conservatives objected to the amount of funding. The two sides attempted to overcome the disagreement, but Republicans decided to craft their own bill after talks dragged on for weeks. The result was a $1.1 billion Zika package that included restrictions on Planned Parenthood and cuts to other federal health programs to offset the cost of the bill.

Democrats continue to object to that measure and hope to revive the earlier bipartisan Senate agreement.

“We passed something here with 89 votes. It went to the House and they sent it back with all of this strange, weird stuff in it,” Senate Minority Leader Harry Reid (D-Nev.) said Tuesday. “It is time to move forward.”

Hoyer said Republicans intentionally added “poison pill” measures that would force Democrats to reject the bill so that they could spend the summer blaming them for blocking the legislation. He said he now expects the two sides to come together to negotiate a deal before the end of the month so long as GOP leaders drop the objectionable elements.

“If $1.1 billion is passed by the Senate on a bipartisan basis and it were put on the floor I think it would pass,” Hoyer said.