Senate leaders spent their last day before the August recess taking parting shots at one another and laying down their markers for the partisan battles to come next month.

Majority Leader Bill Frist (R-Tenn.) appears to be eager for his next opportunity to take on the Democrats, especially with GOP leaders feeling that they outmaneuvered the minority on energy legislation and judicial nominees last week.

“It got under their skin,” Frist said Friday of his tactics against the Democrats. “I probably should have done a little bit more.”

Minority Leader Tom Daschle (D-S.D.) sarcastically said he’s happy to let Frist take credit for last-minute approval of a Democratic energy bill that first passed last year, during Daschle’s time as Majority Leader.

Daschle’s office released a statement Friday declaring that GOP leaders only called up the bill after “fending off criticism from within their own ranks about erratic floor scheduling and [feeling] desperate for achievements to call their own.”

Daschle’s statement added that he would be pleased to let Frist rename various Democratic bills after conservative lawmakers who have opposed such legislation, like changing the Kennedy-Daschle minimum wage hike to the “Santorum-Frist minimum wage increase.”

“If Republicans were prepared to declare victory over passage of a major Democratic bill once, why stop there?” said the statement.

Indeed, a month away from Washington’s humidity is unlikely to temper the Senate’s increasingly partisan rancor, with both sides acknowledging that September’s legislative schedule will likely intensify the vitriol.

“Partisanship has kicked into high gear here. … Now, we’ll move on to appropriations bills and open-ended authorization bills,” one senior Senate GOP aide added. “A minority cannot resist the temptation to ratchet up the rhetoric and throw amendment hand grenades on the Senate floor just for kicks.”

The surprise bipartisan compromise on energy late Thursday evening did nothing to dampen the partisan fuming, and both parties indicated they would use their August recess to prepare for legislative battles to come.

Democrats plan to highlight their policy differences with Republicans by attempting to increase funding for key social programs, such as education and health care, while Republicans have already begun accusing Democrats of fiscal irresponsibility in a time of war and skyrocketing deficits.

Nowhere will that exchange be more on display than in the first days of September, during debate over the Labor-Health and Human Services-Education spending bill, which Frist has vowed to bring up as soon as the Senate reconvenes Sept. 2.

“You’re guaranteed to start off the last part of the session with a knock-down, drag-out fight,” one senior Senate Democratic aide said of the Labor-HHS bill. “It’s always guaranteed to be one of the most contentious bills we do.”

The Labor-HHS bill is just one of nine annual spending bills the Senate still needs to complete, but GOP leaders acknowledged last week that it is unlikely they will be able to finish all the appropriations bills and conference them with the House before the statutory Sept. 30 deadline.

GOP Senators predicted that several stop-gap spending measures, known as “continuing resolutions,” would have to be passed in October and possibly November to keep the government from shutting down.

So far the Senate has only passed four of the 13 fiscal 2004 appropriations bills, while the House has passed 11.

In addition to the Labor-HHS appropriations measure, which attracts controversial amendments ranging from abortion to special education to labor disputes, Frist also plans to serve up a host of red-meat conservative issues in September.

An eight-hour time agreement to again debate the Senate version of a bill to ban an abortion procedure known as “partial-birth abortion” is expected early next month, according to GOP Conference Chairman Rick Santorum (Pa.).

Though both the House and Senate have passed slightly different versions, Sen. Barbara Boxer (D-Calif.) asked for a recorded vote on sending the bill to conference in an attempt to put the majority of her colleagues on record as supporting nonbinding language in the Senate measure endorsing the 1973 Supreme Court case, Roe v. Wade, that made most abortions legal.

GOP leaders also hope to bring up a measure to punish criminals who harm a pregnant woman’s fetus in the course of a crime. It’s an issue abortion rights advocates contend would extend federal law to protection of fetuses, thereby undermining abortion rights. The measure is strongly supported by anti- abortion activists, who deny the bill is linked to the abortion issue.

As another way to excite religious conservatives, GOP leaders also vowed to keep up the pressure on Democrats over their filibusters of three controversial judicial nominees.

In an indication that Republicans feel they have found a salient issue on which to attack those Democratic filibusters, Santorum indicated he would keep alive allegations that Democratic opposition to William Pryor’s nomination to the 11th U.S. Circuit Court of Appeals is based on anti-Catholic bias.

“We have set in motion something our founding fathers would find absolutely despicable … a religious test for office,” said Santorum. “And unfortunately, it looks like it may be just the first of many who will face this kind of scrutiny in the judicial process.”

Democrats have angrily countered that Pryor’s religious affiliation is not the basis for their opposition, and they have repeatedly pointed to Pryor’s questionable fundraising activities for the Republican Attorneys General Association as a reason to hold off on his nomination.

Meanwhile, Senate Democrats hope to give their base voters something to cheer about as well.

Sen. Edward Kennedy (D-Mass.) and other Democratic stalwarts are likely to press an increase in the minimum wage and a hate crimes bill on unrelated measures, said one Senate Democratic aide. Kennedy’s attempts to add such measures to a fiscal 2004 State Department authorization bill in June caused Frist to pull the bill from the Senate floor.

Democrats and Republicans can expect another big fight over whether to move class action lawsuits to federal courts, which traditionally have been less generous in monetary judgments than some state courts.

Last week, Frist told lobbyists supportive of the measure to find the 60 votes necessary to overcome a filibuster, according to two senior GOP aides.

Senate Republicans also hope to salvage an agreement to limit lawsuits from asbestos victims, bring up a measure to ban taxation of Internet sales and consider a measure to limit the liability of gun manufacturers, said one GOP leadership aide.

Frist also set a deadline of the end of September for House and Senate conferees to come to a deal on creating a prescription drug benefit under Medicare. But internal GOP differences over the widely divergent versions as well as Democratic demands that the bill not contain too much private-sector involvement could complicate that goal.

Majority Whip Mitch McConnell (R-Ky.) summed it up before heading out of town.

“There’s much left to be done, and we look forward to continuing with the unfinished business after Labor Day,” he said.