The Republican and Democratic national committees have met in Washington during the past two weeks, and the news is that both parties are in pretty good shape.

The Republicans control two-thirds of the national government--the presidency and the Senate. The Democrats control two-thirds of the state and local governments. Each is prepared to defend what it has and raid the other's territory, in the kind of healthy competition that makes for good government and lively politics.

There would be no news in this, except that we are accustomed to thinking that every institution in America is either going to hell or is already there. Having written at considerable length on the weakness of the parties myself, at various times past, I am personally delighted to see that the invalids are sitting up and taking nourishment.

Just how this came about is not entirely clear, but it is certain that for both Republicans and Democrats, catastrophe was the mother of recovery.

For the GOP, that calamity came in the form of Richard Nixon, who drove his party deeper than ever into minority status with his Watergate crimes and then cost it the presidency via the pardon he obtained from Jerry Ford.

The revival of the GOP organization, under the 1977-80 chairmanship of Bill Brock, began only after everyone in the party had a vivid demonstration of the danger of letting it become a wholly owned subsidiary of a particular president. When he wrecked, the party had no lifeboats of its own.

Though his failings were political, not criminal, Jimmy Carter provided the same lesson to the Democrats, costing them the White House, the Senate and a slew of House seats in 1980.

In both cases, the effect was to revive interest in the party machinery from officeholders, constituencies and interest groups that had deluded themselves into thinking they could make it on their own in Washington--or with just a friend in the White House to lend them a hand.

Since 1980, the Democrats, under their chairman, Charles T. Manatt, have been doing what the Republicans did under Brock: raising money and pumping it back into party-building projects at the state and local level, while cementing relationships with mayors, governors, state legislators and members of Congress.

The Democrats' progress has been less dramatic, so far, than the GOP's under Brock, but it is sufficient to make the Republicans nervous about their financial-organizational edge. After two years in which the Republican National Committee was afraid even to burp without a signal from the Reagan White House, it has a new chairman, Frank J. Fahrenkopf Jr., of Nevada, who at least says he is going back to Brock-style basics, without waiting for Ronald Reagan to decide his own 1984 plans.

The result is a healthy aura of competition, centering around not just the presidency but control of the Senate in 1984 and a multitude of state and local contests-- and the constituencies that decide them.

Manatt was down in Florida last week, pitching for money to the biggest bunch of businessmen the Democrats have been able to corral in years. Fahrenkopf is going to Florida in a couple weeks to tell the AFL- CIO leadership why it would be a mistake for them to sign up early with the Democrats for 1984.

Democrats are finally building an effective direct-mail fund-raising program for themselves, moving into an area where the Republicans have had a virtual monopoly. Republicans, in turn, are finally getting serious about listening to the gripes working women have with the Reagan administration, ending an ostrich policy that was costing the party dearly.

All this comes under the heading of good news, because healthy, competitive parties make for better government. As a case in point, look how the Republicans in Congress, who showed extraordinary cohesion in support of the Reagan program in 1981, have been exerting steady, strong and effective pressure on Reagan for the past year to modify his policies to meet the changed economic and political realities.

That is what should happen in a healthy party. One reason those Republican legislators can do what they are doing is that they know the party will support them strongly --with money and organization--whatever Reagan thinks or does in 1984.

The Democrats are not at that point yet, but they are moving toward it. And that promises that if and when they come back to power, they will not have to suffer the vagaries of another Jimmy Carter--or the dire consequences of his kind of insulated presidency.

It's good news--just what the White House has been begging us reporters to give you. So even if you don't buy a new car or house this week to celebrate the Reagan Recovery, at least send a few bucks to the party of your choice.