In a political season where centrists have been under attack from the increasingly polarized left and right, this week a bipartisan coalition displayed the power of balance and restored the balance of power to the center in the Senate.

Fox News commentator Dick Morris proclaimed in his column for The Hill that “there now exists, in effect, a third-party caucus in the Senate of moderates from both parties.” But such celebrations are premature.

The extremes are entrenched – they have a well-established apparatus of fund-raising and institutional support that the centrists cannot currently equal on a consistent basis. The center has briefly proved that it can hold against enormous pressure on both sides, but it will need to adopt far greater discipline and organization and a more coherent identity if it is to permanently turn the tide and restore proportionate influence to the moderate majority of Americans.

If increasing numbers of militant moderates and middle-of-the-road warriors to stand up and speak out in arenas from town halls, talk radio, blogs, and television to the halls of Congress, they can ultimately win this fight. The bipartisan centrist coalition of 14 senators who stopped the so-called nuclear option and simultaneously secured confirmation for formerly blocked judicial nominees like Priscilla Owen need to hear applause from the broad public that appreciates their independent stand against the party leadership. They will get no such vote of approval from their more partisan colleagues.

Their counterattack has already begun. It was evident in the torrent of criticism from among ideological absolutists and their apologists. One headline from the conservative Michnews.com Web site summed up the tone of the attack: “Seven Cowardly Senate Republicans Surrender, Join Centrist Cabal.” This is the sound of the paranoid style in America rearing its head. In the dictionary, “cabal” is defined as “a plot to carry out some harmful or illegal act” and “conspiracy” is offered as a synonym. The use of the word “cowardly” is instructive as well. In today’s hyperpartisan political dialogue, if you are not an ideological ally, you are automatically considered an enemy. As a result, there is a determined confusion of terms: If someone votes in lockstep with party leadership, they are described as “courageous,” where the far more difficult decision to take a principled stand of independence and vote conscience instead of straight party line is routinely described as cowardly. This is not a little Orwellian.

Look at the 14 members of the bipartisan centrist coalition and it is evident that they are a balanced combination of Blue-State Republicans and Red-State Democrats, Senate traditionalists and independent-minded mavericks. There are Olympia Snowe and Susan Collins from Maine, Lincoln Chafee from Rhode Island, Mark Pryor from Arkansas, Mary Landrieu from Louisiana, Ken Salazar from Colorado, and Ben Nelson from Nebraska. Arizona’s John McCain and Connecticut’s Joseph Lieberman are always steady leaders of the independent center in the Senate, but they were joined out of principle by figures ranging from South Carolina’s Lindsay Graham, Ohio’s Mike DeWine, Hawaii’s Daniel Inouye, West Virginia’s Robert Byrd, and Virginia’s John Warner. This is not an ad hoc collection of special interests but a broad and representative cross section of America fighting for what they perceive to be the national interest.

The existence of such a coalition shouldn’t come as a surprise. Moderate Republicans and moderate Democrats share more policy positions in common than they do with the more extreme wings of their own party. Their party affiliation is largely a matter of local political dynamics rather than deep differences of national perspective – these are folks who likely admire both Teddy Roosevelt and John F. Kennedy, Harry Truman and Ronald Reagan (for that matter, it’s worth remembering that Ronald Reagan admired Harry Truman, and campaigned for him in 1948).

In the past, the Senate could be depended to serve as the founding fathers intended – as a civil and statesmanlike check on the more nakedly partisan rough-and-tumble of the House of Representatives. But polarization in congressional voting patterns has increased steadily over the past 25 years, an ideological phenomenon that has been matched by declining party registration among the public and dramatic concurrent growth in the number of independent registered voters. Whereas once party leadership provided the moderating force in Congress, now it is up to bipartisan centrist coalitions to provide such balance.

There is reason for centrist candidates and centrist citizens to feel confidence about their long-term prospects. Seventy-nine percent of American adults favor moderate candidates, while more than four out of five say we need more elected officials who are willing to vote independently rather than strictly along party lines, according to a new Harris Interactive Poll. But while it makes sense that centrist elected officials should hold the balance of power in a country that is closely divided politically, the ideological elites who feel deeply divided have taken control of the parties.

Going forward, centrists cannot afford the luxury of incoherence and indecision: Weakness will only serve as a provocation to professional partisans and ideological absolutists on both sides. If strong centrists are to revive our national search for common ground, moderate voters will have to identify themselves actively as centrists and independents, while members of the growing House and Senate centrist coalitions will have to work together more closely across party lines with greater constancy and sense of purpose.