January 3, 2001 brings with it a remarkable opening to the 107th Congress. A majority party that has only in effect a 7-seat margin controls the House of Representatives. The Senate is tied for control - each party controls 50 seats. Just to establish the organization of the Senate, including the designation of the majority leader and committee seat distributions, will require that the vice-president cast a tie-breaking vote, the first of what promises to be many such votes over the next two years. Although the federal government is technically unified, the Republican president did not win a plurality of the popular vote, which further clouds any clear policy mandate the Republican majority may wish to claim.

There is one immediate effect on Congress that will result from the 50-50 tie in the Senate and that is the melding of the executive and legislative branches. The vice-president will necessarily spend more active time in the chair, presiding over the Senate, than any other vice-president in the last 50 years. The fact that the majority party in the Senate will need the support of the vice-president to pass legislation in the Senate itself will force more than usual cooperation between the Senate and the executive under unified government. Typically senators in the majority party in the Senate work closely with the executive branch to craft legislation, but always maintain their institutional prerogatives to bargain on behalf of the constituents in their states. However, the next two years will be quite different in this regard. Senators in the majority party will know that it is unlikely that they can pass any bill without the direct intervention of the vice-president, which severely limits their ability to bargain independently with the White House. Consequently, the power of the Senate to function as a check on the executive branch will be constrained.

On the opposite side of the coin is the increased association the president will have to share with his congressional party. History has shown us that when it serves his interest, a president will oppose Congress, even when it is controlled by members of his own party. In this case, it will be far more difficult for President Bush to disassociate himself from Congress when his own vice-president will be casting votes in the Senate to help pass majority party bills. Given the open and highly visible operations of the Senate to the American public, the president will be forced to share more accountability for congressional behavior than he might otherwise.

We might expect that the balance of power forces party unity within both the Republican and the Democratic Senate caucuses because any defection means an automatic loss on the floor. However, the larger macro relationship between the Senate and the president may very well produce the opposite results and force more bipartisan cooperation. There are two scenarios that might make such cooperation likely. The first scenario may resemble that of NAFTA, when President Clinton sought the support of the opposition party in order to pass his preferred policy. President Bush may seek policies that are not supported by the entire Republican Senate caucus, and consequently he may reach across the aisle to cut deals with Senate Democrats. However, should he do so, he undercuts the continuing power of the Republican majority, as enforced by the vice-president as the presiding officer. In that way, the executive-legislative branch relationship may very well resemble parliamentary government more so now than at any time in its past history.

The other scenario is one in which a core group of senators from each party prefers a policy that is in opposition to the president, and they band together to assert the institutional power of the Senate vis-à-vis the executive branch. It is more likely that such an alliance would occur over distributive policy; one can imagine senators from states of a certain size, or from a region, banding together to oppose administration policy. It would be less costly for members of the majority party in the Senate to defect on issues that have a clear and direct bearing on their state constituents, than on larger macro policy issues, and given the precarious nature of the Senate majority as currently constructed, separating oneself from the party may be the best individual level strategy in the Senate.

There are two directions therefore that the Senate might be expected to go over the immediate future, and in fact, over the next decade. The Senate could continue in its current pattern of intense partisan division, and the slim majorities that either party might enjoy would result in stronger and more cohesive party caucuses. In simple terms, the costs of defection from the party line under these conditions would be too high. As parties cohere over time, senators' party identifications will become a more important component of their overall reputations. On the other hand, the constant instability associated with slim majorities could make Senate party caucuses more divisive and insecure, which would decrease the value of the party label to individual senators. As a result, senators may once again return to the more individualistic tendencies that marked the Senate of the 1980s and early 1990s.

If the members of the Senate choose to embrace partisan division, and the members of the majority party cooperate with their party's president whereas members of the minority party assume the mantle of the opposition party, we could see a renewal of clear and distinct national party platforms and policies. In that way, partisanship in the Senate, while perceived to be a short term minus, could end up being a long term benefit to the American political system.