After indicating that she could live with the Stupak amendment in an interview Monday morning, Sen. Claire McCaskill (D-Mo.) said tonight that she opposes the measure because it overreaches in restricting access to abortions.

Her words mark a slight change of attitude from this morning, when she suggested on MSNBC that the amendment offered by Rep. Bart Stupak (D-Mich.) to the House's healthcare bill was the price supporters of Democratic healthcare reform would have to pay in order for a bill to pass Congress. 

McCaskill made her remarks on Twitter this evening:

Oppose Stupak.Don't think we should change current law which is no public $ for abortions,but amndmt goes too far limitng private funds too

Supporters of the amendment, who include centrist and conservative Democrats and Republicans, say the amendment is necessary to prevent tax dollars or subsidies from funding abortions under the public health insurance plans and the insurance exchange included in the House bill. Opponents of the measure, who include liberal Democrats, say it restricting access to abortions to the point that private health insurance plans could be affected.

A group of 40 Democratic lawmakers, led by Reps. Diana DeGette (D-Colo.) and Louise Slaughter (D-N.Y.) have threatened to sink the healthcare bill should it emerge from conference with the language included. Chief deputy whip Rep. Debbie Wasserman Schultz (D-Fla.) also said that she is confident that the bill would not contain the Stupak amendment.

McCaskill did not say whether or not she would block the bill should it include the abortion provisions. The centrist senator did describe her self as a "pro-choice candidate" during her interview this morning.

The House passed their version of healthcare reform legislation with the help of some of the 64 Democrats who voted for the Stupak amendment. The Senate now must pass their healthcare bill. A conference committee will then resolve differences in the two bills. Some Democrats have vowed to use the conference process to strip the bill of the amendment.

It remains unclear how the abortion debate will affect the Senate's bill. Republicans have said they would seek similar language in the upper chamber's bill while some centrist Democrats have wavered on the language. 

The only Republican to vote for the House bill, Rep. Joseph Cao (R-La.), favored the amendment. Sen. Susan Collins (R-Maine), a Republican that Democrats may court to support the Senate bill, said today that she opposes the abortion provisions.

Cross-posted to the Briefing Room 

UPDATED 2:06 p.m.

McCaskill's office stressed that her tweet does not represent a change in position on the Stupak abortion amendment.

McCaskill spokeswoman Maria Speiser pointed to one of the senator's tweets made late last night:

Asked this morning my opinion on whether Stupak amndmnt would kill the bill (said prob no) and NOT asked my opinion of the amndmnt. Im opposed