As is well known, the framers of the constitution considered partisanship -- or "faction," to use their term -- one of the main enemies of democracy. Given this distrust of faction, it seems likely that Article I, Section 2, clause 5a's requirement that "The House of Representatives shall choose their Speaker and other Officers...." was mainly administrative in intent. The model was probably the Speaker of the British Parliament, whose role was to be even-handed in the divvying up of administrative perquisites and keeping order during floor debates. A vestige of this original conception can be seen in the tradition that the Speaker of the House is not supposed to vote on legislation himself except to break a tie. He's meant to run the vote fairly and even-handedly.
In fact, the Speaker of the House has almost from the very beginning been a partisan office. With the emergence of the two-party system in the elections of 1796 and 1800, the Speaker began to be selected from the leadership of the larger of the two parties, and the partisanship of the office was accentuated during periods in which the Speaker was from a different Party from the President, and thus could cast himself as more of a "prime minister" -- a vision of the speakership recaptured most dramatically in recent years with Newt Gingrich's attempt to completely sideline Bill Clinton in 1995.
In the earliest Congresses, each legislative bill introduced in the House had a "floor manager," typically the Representative who had introduced the legislation; legislation was not seen as a partisan matter. Again, it was only with the solidifying of the two-party system in the early 19th century that the national Parties began to be seen as having coherent legislative agendas. During his various tenures as Speaker during the 1810s-20s, Henry Clay explicitly saw himself as responsible for pushing through his Party's legislative program. Thus in a functional sense, Clay became the earliest "House Majority Leader."
It was after the Civil War that the modern leadership system of the two parties gradually emerged. With the end of Reconstruction (1877), and the reemergence of the Democratic Party as a national force, the shifting minority party began to institutionalize the role of a head of the opposition, who was also a kind of "Speaker in waiting" -- waiting for his party to become the majority, that is. This was really a nascent "Minority Leader" position. This notion that the Minority Leader was a Speaker in waiting only made sense given that the Speaker of the House was the de facto "Majority Leader."
Yet even as the Speakers were quite clear that they were leading their party in House of Representative, there also remained the notion that the Speaker should be above his party, imposing his own political vision upon the whole House. This recuperation of the idea that the Speaker had a larger, more national and less partisan function was a natural byproduct of the extreme weakness of the Presidency in the late nineteenth century. (Can you name a single accomplishment of the Presidency during the twenty years that the office was occupied by Presidents Hayes, Garfield, Arthur, Cleveland, and Harrison?)
But having the Speaker take on this larger, more statesmanlike function meant that the ruling party needed an actual floor leader, a true Majority Leader separate from the Speaker. Such a role emerged formally in 1899, when Speaker David B. Henderson, to uphold the noble fiction of his own nonpartisanship, designated Representative Sereno Payne to act as his "agent" on the House floor; the office of Majority Leader, separate from that of the Speaker, has existed ever since.
As for the Whips, here's a succinct take on their role:
Also in 1899, the Majority first chose a "Whip" (a term already, by then, of long use in the British Parliament, itself deriving from the term used to describe the man whose job it was, during a foxhunt, to keep the hounds from straying); the Minority followed suit toward the end of that same Congress (the 56th). The job of these Whips -- besides acting as floor leader in the absence of their respective Party's leader -- has traditionally been to keep his or her Party's leader apprised of who is -- and who is not -- toeing the Party line as a floor vote looms; Majority Whips tend to be of the same faction within the Party as the Majority Leader and Speaker (since it is the Majority that has the power to push through their legislative agenda: thus, everybody must be on the same "page"), while Minority Whips are often of a different faction of the Party than the Minority Leader.This brief history helps us form a clearer picture of what is going on in the current Congress. First, we have Speaker Dennis Hastert (who by all reports is the dominant power in the House despite the fact that Tom DeLay gets more headlines), who represents and promotes an extremist Kinder, Küche, Kirche vision of America. Although, as Speaker, Hastert casts himself as an avuncular man who is above the partisan fray, he in fact eschews any notion that the Speaker should promote a bipartisan political vision. He has no interest in trying to work with the Democrats to achieve his goals; he simply want to sideline them.
Supporting him in this effort are House Majority Whip Roy Blunt and House Majority Leader Tom DeLay, the latter of which is by now well understood to represent an extremist and ethics-free position, but who as Majority Leader need make no apologies for his partisanship. As the duo charged with ensuring that the Republican Party votes as a unified bloc, these guys lead the "majority of the majority" faction of the Republican Party that believes their 27% has a mandate to do as they please. Their unprecedented ability to maintain voting discipline has allowed this faction to steamroll a extremist legislative agenda, even in the face of more than 2-to-1 national opposition -- ethics, science, fiscal sanity, majoritarian sentimentality, and liberal weenies be damned.
When you compare the unity and discipline of the Republicans' "majority of the majority" leadership to the leadership of the House Democrats, the difference could scarcely be more striking. As Minority Leader, Nancy Pelosi (who represents San Francisco) duly takes as divisive a position nationally as Hastert does. However, the House Minority Whip, Steny Hoyer, represents a totally different Democratic faction from Pelosi.
In short, whereas the Democrats' leadership typifies their Party's sorry lack of discipline but salutary pluralism, the Republicans' leadership typifies its Party's monolithic, authoritarian salute-the-flaggism. That certainly makes the Republicans better suited to use political power to their advantage, but it certainly does not mean that they are doing what the majority of the country wants.