Faced with an avalanche of agenda must-haves and legislative must-dos, Senate Majority Leader Bill Frist (R-Tenn.) is looking to shift as early as July to a “dual track” process that will divide the chamber’s daily sessions between appropriations bills and reauthorizations.

The schedule is fraught with hazards and leaves little room for error. Mindful of this, the GOP leadership has made the decision to set aside the month of June for consideration of Medicare reforms that will enable the program to carry a prescription drug benefit, while devoting the greater part of July to the megalithic reauthorizations of the highway and airport trust funds.

Much will depend, however, on the progress through May on key pieces of unfinished business, including two items — President Bush’s economic growth package and energy bill — that Republican leaders consider to be as important as they are controversial.

As it is, the sheer volume of activity ensures that space will have to be found or made for the almost-must-dos, such as the reauthorization of welfare reform, which was supposed to be done last year.

“I don’t think there’s any question but that this is going to be a very busy, active year,” said Bill Hoagland, a senior adviser to Frist. Looking at the overall picture, Hoagland added, “It’s a good thing we’re at the beginning of the 108th Congress and not at the end of the 108th Congress.”

Frist has scheduled consideration of the welfare bill, which was supposed to have been completed last year, for late July, depending on progress with the highway and airport measures, known around Congress as TEA-21 and AIR-21.

Whether the Senate can also complete its reauthorization of funding for special education by the August recess is an open question. That legislation is nearly as controversial as welfare reform, and remains tied up in the Senate Health, Education, Labor and Pensions Committee while negotiators try to eliminate as many differences as possible.

As with nearly all reauthorizations, there is no absolute need to complete the welfare and special education bills, because Congress can simply extend them at their current levels indefinitely. But the measures are nonetheless de facto necessities, like the highway bill, because Members have long sought what they consider to be critical revisions to the programs.

One complicating factor in the schedule is that there are reauthorizations that must in fact get done. Among these is an extension of federal language that keeps states from adopting their own standards regarding the information that can be reported to credit agencies.

The failure to get an extension could wreak havoc on the credit markets, but the issue is a key battleground in a hot debate over privacy rights.

“It’s definitely going to be an interesting debate,” said Andrew Gray, a spokesman for the Senate Banking Committee, which will begin its hearings on the matter on May 15.

Meanwhile, under pain of as much as $4 billion in possible trade sanctions from Europe, Congress is being forced to reconsider a number of tax breaks given to American exporters through foreign sales corporations.

This matter was forced onto the Congressional agenda by a late-March ruling at the World Trade Organization, which judged that steel tariffs imposed by the Bush administration last year were illegal. Altering U.S. law to comply with the WTO’s decision will be no mean trick, in part because many Democrats considered even the guilty tariffs to be too low.

Some measures that Republicans consider critical to their agenda are already gathering pace. Bush’s endorsement on Tuesday of legislation to fight AIDS in Africa — an agenda piece that emerged from his State of the Union address in January — tagged that bill for a fast track through Congress.

The endorsement, combined with the House GOP leadership’s decision to bring the bill to a floor vote today, was apparently enough to defuse plans at the House Energy and Commerce Committee to tinker with it. A spokesman for Senate Minority Leader Tom Daschle (D-S.D.) said the Africa/AIDS legislation is among the top near-term priorities for Senate Democrats, and GOP sources said that Frist and Senate Foreign Relations Chairman Dick Lugar (R-Ind.) are nearing agreement on a bill that closely resembles the House package.

But on its way to passage the legislation will still have to run a gauntlet of irate social conservatives, who contend that the House International Relations Committee bill — the legislation Bush endorsed — does not do enough to promote abstinence and prevent money from reaching the hands of agencies in Africa that provide abortion services.

Perhaps emboldened by at least tentative victories in opposing Bush nominees for the federal judiciary and plans for oil drilling in the Arctic National Wildlife Refuge, Democrats have quietly been questioning Frist’s ability to move key Republican initiatives through the chamber.

“His ability to get through the president’s priorities, with which many Democrats disagree, has been unpromising so far,” one Senate Democrat said, citing the ANWR proposal and the judges, among other things.

The source noted that two other key priorities for Democrats — the growth package and prescription drug initiative — dovetail with items at the top of the GOP list, but suggested Republicans could face some difficult obstacles on these measures unless they show themselves willing to make some concessions to the minority.

“The White House and the Republican leadership have to understand that in order to get things done there’s going to have to be some compromise,” the Democrat said. “Without the compromise, you just can’t get these kinds of things through such a narrow-majority Senate.”

The dual-track process has become a staple of the modern Senate, though its efficacy has been thrown into question as the majority has narrowed to a virtual 50-50 split. Virtually no legislation, including the must-do spending bills, moved when Democrats ran the Senate for most of the 107th Congress.

A batch of appropriations measures for fiscal 2003 were eventually lumped into an omnibus bill and passed at the beginning of the current session, after the majority had changed hands.