While money is the primary influence on the conduct of both major parties I have come up with a shorthand definition to distinguish between them: Democrats are systems managers, Republican used car salesmen.
The Coakley-Brown match up in Massachusetts, even though both candidates are attorneys, illustrates this nicely.
Scott Brown is running, as nearly every Republican has since 1980, as a Washington, D.C. outsider and champion of smaller government, i.e. cut welfare for the poor and cut taxes for the rich. Never mind that as a lieutenant-colonel in the Massachusetts Nation Guard Brown's sucked off Uncle Sam's tit for thirty years, knowing, in this day and age of the All Volunteer Force our soldiers and Marines and National Guardsmen are sacrosanct heroes whose asses the rest of us must kiss with great regularity, I'll get some flack for even entertaining this thought.
And even though Brown maintains a law practice focusing on divorce and adoptions, for most of his adult life, when he wasn't collecting a US Treasury check for one-weekend a month and three weeks a year with the Guard, he has been since 1992 a professional politician. Yet he sells himself as some one untainted by big money politics. Absolute bullshit which the teabaggers are eating up with gusto as they have since 1980. Some people never get it.
Coakley, on the other hand, is a long time law-and-order Democrat, a prosecutor since 1982. She's the kind of competent systems manager, i.e. coordinator, the establishment Democratic Party elders love so much these days. Intelligent, bland and a good administrator, Coakley is the kind of politician who would be good at running a state or federal agency, as she does in her capacity as Massachusetts Attorney General.
So what this election boils down to is, colorless though competent jurist versus a huckster, a lawyer-huckster at that.
So when some one tells you there isn't a dime's worth of difference between the two major political parties, you can say there is: Democrats are systems managers, Republicans used car salesmen. One party, the Democrats, is content to competently manage the status quo. The other, the Republicans, sees the status quo as a means to an end for self-aggrandizement and enrichment at their teabagger partisans' expense for the benefit of their major political campaign donors.