Sen. Ted Cruz and his colleagues continued making floor speeches through the night, showing no sign of letting up as the sun rose over the Capitol on Wednesday.
The Texas Republican got no shortage of help in the overnight hours, especially from Sen. Mike Lee, R-Utah.
At one point, Lee delivered an impromptu constitutional law seminar (in the form of a question, at least nominally), discussing the history of the Commerce Clause, including the decision in Wickard v. Filburn, in which a farmer produced more wheat than was allowed by federal law.
That case has long been criticized by conservatives for representing a time when, in their view, the Supreme Court took an overly expansive view of the federal government's role.
Cruz aides were praising Lee for providing a much-needed assist to the effort, which kicked off at 2:41 p.m. Tuesday.
Cruz has controlled the floor longer than the senators involved in some of the chamber's most memorable long speeches, including the effort earlier this year by Kentucky Republican Rand Paul.
Cruz and his Senate supporters are speaking to encourage fellow Republicans to oppose a bid by Majority Leader Harry Reid to strike out language in the stopgap spending measure the House passed last week that would defund Obamacare.
Senate Republicans are opposed to implementing the 2010 health care overhaul law, but many disagree with the tactic favored by Cruz and Lee, which would require GOP senators to vote against limiting debate on the House-passed continuing resolution that they support.
In any event, under Senate rules, the cloture vote that Reid set up Monday will trump Cruz at noon, with the vote coming automatically at 1 p.m.