How many voters does a candidate need?

With understandable dismay, David Brooks cites a quote from an interview one of Hillary Clinton's advisers gave to the New York Times: "If you run a campaign trying to appeal to 60 to 70 per cent of the electorate, you're not going to run a very compelling campaign for the voters you need," said David Plouffe. Brooks disapproves because this seems to indicate that Clinton is going to run a narrow campaign aimed at maximizing turnout from Democrats' base voters instead of building a broader coalition. His opinion aside -- Brooks believes Clinton should run a "centrist" campaign on her husband's model -- you can wonder why a candidate would rather have 52% of the vote than something between 60% and 70%. But there's some implicit realism to Plouffe's point, if we understand him to mean that it's impossible at this point in our history for any party or candidate to get between 60% and 70% of the popular vote, let alone the electoral vote. Yet he seems to be saying more than that. He seems to be saying that appealing to a broader electorate risks alienating your most dependable voters. That assumption reveals a problem with partisanship. Plouffe appears to assume that Clinton will do better if she presents herself as the candidate, and actually the representative, of her party base rather than as the presumed representative of the entire American people. It also reveals a problem with apathy on one hand and partisanship on the other. Part of the problem of shooting for 60-70% of the vote is that you'd need to appeal to people who don't normally vote. You can't know whether devoting time to them will pay off in November, while your base voters, for ideological or identity-politics reasons, can be depended on, as long as you tell them what they want to hear. Brooks suspects that Clinton may take it for granted that the permanent presidential majority for Democrats, upon which Obama depended, is already in place, so that if you follow Obama's model no Republican can beat you. Brooks thinks that's a premature conclusion, and that a significant portion of the electorate is still open to persuasion and could swing from one party to the other. But his only alternative is for Clinton to occupy a middle ground between the major parties rather than reach for 60-70% by expanding the electorate. If for Plouffe the key to victory is to energize the base, for Brooks the key is to blend Democratic and Republican (or liberal and conservative) policies into a moderately palatable mix. Neither considers the possibility that a 60-70% majority could be had by offering Americans something entirely different. It's widely assumed that many Americans don't vote because they can't make up their minds between the major parties or are equally disgusted with them. It could be said that these non-voters don't really know what they want. But what if many of them had a more clear idea of what they want than they're given credit for, yet the Republicans and Democrats alike don't want to give it to them? Merely mixing Democratic and Republican positions into a centrist stew won't reach the millions who are not in the middle but outside the conventional consensus. There's no guaranteeing that these millions have coherent, complementary ideas about our nation's future, but if politicians or parties emerged with a better understanding of what they want, or at least a greater interest in learning what they want, then even the major parties might worry about the solidity of their bases against the tide of a real American majority. Wishful thinking, yes, but what else should we imagine, when our political strategists and our pundits seem so unimaginative?