Politico’s Carrie Budoff Brown reports that one particular issue could cause a spontaneous abortion of the ObamaCare bill in the Senate, and it’s not its overwhelming slate of new taxes.  Ben Nelson (D-NE) says he has “drawn a line in the sand” over public funding of abortions and abortion coverage, and will filibuster any bill that does not contain the same kind of language that Bart Stupak (D-MI) added to the House version of the bill.  Other liberal Democrats say they will not support a bill that has that kind of restrictive language in it.  Instead of coming closer on compromise, the abortion issue threatens to derail the entire bill:

In the past week, abortion has flared up as a major impediment to passage of a health care reform bill in the Senate, taking a similar path as it did during the House debate — from obscurity to obstacle in a matter of days.

After months of trying to craft a 60-vote coalition based on the finer points of health care policy, Senate Democrats are growing increasingly worried that abortion will upend what had become a clear path to approving the overhaul bill.

Sen. Ben Nelson (D-Neb.) sparked a fresh round of concern this week when he repeatedly and definitively vowed to filibuster the health care legislation unless it included abortion restrictions as tough as the so-called Stupak amendment in the House bill.

“I don’t ordinarily draw a line in the sand, but I have drawn a line in the sand,” Nelson said Friday.

Nelson certainly has a long history of agitating his party by withholding his vote until he wrings out every last concession from Senate leaders. But on the uncompromising issue of abortion, Democrats fear he may really be serious this time.

Nelson knows that Nebraskans aren’t terribly enthusiastic for ObamaCare anyway, but they’ll throw him out of office if he makes them pay for abortions.  That makes him as serious as, well, a heart attack — just as Stupak was serious about at least getting the vote.  He may not be the only one in his caucus looking at the issue through electoral-colored glasses, either.  Politico named Blanche Lincoln the most endangered Senate Democrat in the next cycle, and she will need some way to reconnect to conservative Arkansans between now and next November.

Of course, Harry Reid is vying for that title, too, and a failure to get a bill out of the Senate will make him look impotent, which isn’t exactly the antidote to his 38% job approval rating in Nevada.  But it’s a numbers game, and Reid doesn’t have them.  Without a Stupak-like amendment that satisfies Nelson and perhaps Lincoln, he can’t get to 60.  With a public option, he loses Lieberman, and perhaps Lincoln and Nelson again, and can’t get to 60.  If he adds Stupak language to the bill, he’ll lose his progressives, and without a public option, he won’t even get to 50 votes.

There may be ways out of this thicket, but they’re becoming less and less likely to work.