As the deadline dawns for lawmakers to pass a budget for the rest of the fiscal year, Republicans and Democrats are pretty close, spending-wise ($7 billion apart, last time we checked, which is a tiny fraction of the whole budget). The real hold-up, now, is a series of so-called riders, or policy changes, that Republicans want to attach to any budget bill, and that Democrats won't accept. Using budget riders to alter policy is nothing new, but the changes at issue this time cut to some of the core values of each party: abortion and environmental regulation. Mostly abortion.

One Republican rider would abolish federal funding for Planned Parenthood, the nation's largest abortion provider. That group has long said it doesn't use federal money to pay for abortions (that would be illegal, after all), but as the Washington Post points out, "conservatives have questioned the integrity of the group and argued that federal funding frees up other money that Planned Parenthood can use for abortions, while liberals say that taking away funding would harm women’s health efforts."

Another rider would once more bar the District of Columbia from spending local tax dollars on abortions for poor women. The New York Times notes: "Because this law was on the books for years — passed by Democrats as a rider to unrelated bills — it has perhaps the best chance of surviving in any spending compromise." Republicans are also trying to halt funding for abortions in other countries, and to stop the U.S. contribution to the United Nations Population Fund.

On the environmental front, a series of riders would limit the reach of the Environmental Protection Agency, curbing its ability to regulate greenhouse gas emissions. They would also stop or suspend new and existing regulations.

As John Boehner, Harry Reid and Barack Obama got through one more unsuccessful budget meeting last night, the public debate has been about compromise, but individually, the barbs from politicians on Twitter tell a different story. Senator Jim DeMint, of South Carolina, tweeted last night: "Dems to force shutdown & stop troop funding unless taxpayers forced to fund abortions in DC: " and Boehner himself announced, "It’s become sadly evident to me that the White House and Senate Democrats are just not serious yet about enacting real spending cuts."

On the left, New York Representative Anthony Weiner tweeted yesterday, "Lets stop saying the differences are small. The GOP refuses to deal unless we defund Planned Parenthood." Nancy Pelosi gave a nod to yesterday's Planned Parenthood rally, tweeting, "Thanks to everyone at the at the Capitol for standing up for women’s health - I stand with you!"

At some point, somebody's obviously going to have to concede in this debate. But with issues like this at stake, most in Congress would rather be seen to be making a stand. A very expensive stand.