Sen. Claire McCaskill (D-Mo.) said Wednesday she hasn't decided how she'll vote on a bill extending certain benefits, leaving open the prospect of breaking with her fellow Democrats.

McCaskill said she supports a number of benefits in an extenders bill before the Senate but, like Republicans, she worries about the indefinite extension of benefits that aren't paid for by cuts elsewhere in the budget.

"At this point, I am still weighing the pros and cons of both provisions," the budget-hawking senator said Wednesday in a conference call with Missouri reporters.

McCaskill said she supports some of the small-business and research-and-development tax credits in the bill, but that she does not like other parts, specifically a number of portions not being paid for.

Democrats have said that the spending is considered an "emergency" and is exempt from pay-as-you-go (PAYGO) rules. Republicans reject that argument, and have offered legislative attempts at offsetting the spending in the benefits extensions.

"I certainly understand we've had an emergency, and my votes have been for extending unemployment because of the emergency, and the crisis in our economy, and the pain that people have had that have been out of work, and have had difficulty in finding work," McCaskill said. "But to continue to extend, in an unprecedented fashion, unemployment benefits — indefinitely, without any kind of decision as to how this would end — I think is a mistake."

She said that if lawmakers were to extend benefits one more time, it should be the last time, followed by a return to the normal schedule of unemployment benefits distribution at the end of this latest extension.