Neither the DP nor the RP has a base in that sense nor has either ever had one. The only base either party has is made up of local party organizations. Local elected officials (e.g., the Daley machine in Chicago). Local and State labor bureaucrats. Local NOW or NAACP chapters. A few small businessmen (even in areas controlled by the opposing party), etc. The political principles of these local organizations are for the most part whatever principles will maintain the organization in existence. In scattered cases that means principles which would appeal to leftists, but with almost no exceptions, these particular local organizations are practical leftists, that is they will go through all the motions of pushing their politics, but in the last instance will always join in the unanimous nomination of the winner at the Convention and campaign for him or her.
References to the DP's base on this list confuse the _base_ of the party with the large masses of "abstract -- isolated -- individuals" who can be shuffled to the polls by these organizations or can be corraled by TV ads. But these voters are no part at all of The Party -- either its base or its leadership. And they cannot be reached by working "inside" the DP because that is not where they are, except for 5 minutes every 4 years (for some of them every 2 years). The last place on earth to go looking for DP voters is inside the DP. I agree, of course, that when a left appears in this country, it will consist mostly of DP voters. But as long as the Myth of the DP survives, leftists won't put the brains to work figuring out how to 'get' these voters for left causes.
Carrol