First acrimony, then an apology, then more acrimony, more apologies and finally some good behavior.

Partisan discord on the Senate floor became so pronounced Thursday that at one point a Republican leader sided with the opposition to try to settle frayed senators.

Majority Leader Harry Reid, D-Nev., opened the day with a public declaration of regret over his behavior the night before, during a tussle with Sen. John Cornyn, R-Texas, over a colleague’s amendment to the Homeland Security spending bill (S 1644).

“I didn’t get my way so I thought I would throw just a little tantrum, and the evening has brought to my attention that I was wrong and Sen. Cornyn was right,” Reid said.

The amendment — which added $3 billion for Border Patrol agents, detention beds and fencing along the border — was adopted on an 89-1 vote.

All was calm, at least on the surface, for a few hours.

But tensions were still running high enough that when Sen. David Vitter, R-La., spoke out of turn in seeking to modify his own amendment dealing with prescription drugs from Canada, verbal retribution rained down.

Reid and the bill’s Democratic floor managers, Patty Murray of Washington and Robert C. Byrd of West Virginia, all scolded him.

“I’m disappointed that the senator from Louisiana decided to delay consideration of a bill that includes critical funds for aiding the victims of Hurricane Katrina,” Byrd said. “Did you hear me?”

Vitter immediately offered to withdraw his amendment, saying, “I apologize if anything was miscommunicated regarding the last hour or so.”

A short storm was followed by an even shorter calm. Within a few minutes, Sen. Jim DeMint, R-S.C., challenged an amendment about hunting Osama bin Laden, saying it breached a rule against authorizing on an appropriations bill.

DeMint won a verbal ruling from the chair.

But winning wasn’t enough.

He said he wanted a roll call, arguing that the rule was being enforced against Republicans more than Democrats.

At that point, even his colleagues became skeptical.

“I just think we need to calm down around here,” said Minority Whip Trent Lott, R-Miss., stepping into the skirmish. “I plead to my friend from South Carolina, this doesn’t prove anything to have us vote on something that is . . . you’ve already won.”

Senators finally settled down — without the vote — and testily returned to work.

First posted July 26, 2007 7:06 p.m.