A dispute on federal funding for abortions and restraining an environmental agency's actions may be the insurmountable sticking points that trigger a government shutdown as lawmakers struggle to reach a deal to fund the government for the rest of the fiscal year.

Lawmakers are attempting to pass a six-month budget extension by April 8. Failing to do so will put about 800,000 federal employees on temporary leave until funding is secured. After three meetings between President Barack Obama, Senate Democrats and House Republicans, no deal has been reached.

Lawmakers agreed late Wednesday that 'some progress' had been made in talks but the rhetoric hardened on Wednesday. Lawmakers will meet for the fourth time with President Obama on Thursday night.

Meanwhile the Republican-controlled House passed a separate one week extension that would fund the military for six months while making $12 billion in cuts, a measure Obama has threatened to veto if the Democratic Party-controlled Senate passes, saying a solution on the entire budget must be passed.

Secretary of Defense Robert Gates said Thursday that if there is a shutdown, soldiers would receive half a their paycheck on April 8. If the shutdown extends from the 15th of the month to the 30th, soldiers would not receive a check. Eventually it would be repaid once there was an agreement.

This debate used to be about saving money. That is no longer the case, Senate Majority Harry Reid D-NV said on Tuesday in prepared remarks about the ongoing negotiations.

The Tea Party is trying to push its extreme social agenda - issues that have nothing to do with funding the government, Reid said.

We are very close on the cuts and how we make them, he said. [T]he only things - holding up an agreement are women's health and clean air.

Earlier in the day House Speaker John Boehner, R-OH, said it was common practice in Congress to attach policy riders to budget bills.

It's been a longtime practice of the House and Senate to not only set spending levels but also dictate how that money is to be spent because the Constitution requires us to determine how spending will occur, he said.

Boehner also said that there were a number of issues outstanding, adding that any attempt to narrow this to one or two issues would not be accurate.

In an interview on Good Morning America on Thursday, Boehner said there was no daylight between him and the Tea Party

What they want is, they want us to cut spending. They want us to deal with this crushing debt that's going to crush the future for our kids and grandkids. There's no daylight there, he said.