Even though I've played a lot of poker, shot craps in Las Vegas and wagered a few bundles that the Washington Redskins would whup the Dallas Cowboys, I've remained mildly opposed to a national lottery.

I've had my head cluttered up with the ''moral'' arguments that criminals would take over, poor people would be exploited, children would starve as their daddies became compulsive gamblers -- and, of course, that it is horrible to have government-sanctioned gambling.

Well, I've sorted it all out, and I say, bring on a national lottery!

Estimates that seem reliable indicate that Americans gambled about $190 billion last year on slot machines and other casino games, church bingo, state lotteries, horse races, prize fights, football, basketball and baseball games -- not to mention the illegal numbers games and who is going to par which hole on a golf course.

Why shouldn't the federal government take some of the gamblers' money so as to reduce a federal deficit that cowardly politicians won't touch with a direct tax increase?

Because organized crime would move in, lottery opponents say. They ignore the fact that the lotteries operated by 22 states and the District of Columbia last year were, with rare exceptions, clean of corruption and graft.

Someone wagering in a lottery knew it when his winning number came up, which is more than could be said for millions of investors in Wall Street stock markets.

If the Catholic Church can sanction bingo gambling and retain its moral clout, I'm not worried about a lottery ruining the reputation of politicians.

But what about the fact that a national lottery would be a regressive tax, hurting poor people the most? It can be demonstrated that almost everything hurts poor people the most -- including the budget deficit, the trade deficit and the budget cuts that represent futile attempts to reduce the deficits.

More than $12 billion worth of tickets were sold in state lotteries last year, netting almost $5 billion for education, services for the elderly, parks, highways and other projects. A lot of poor people benefited.

America will never again be competitive in world trade until it stops under-educating perhaps a quarter of its young people. If funds from a national lottery were earmarked for equalizing educational opportunities, and for enabling millions of youngsters to live in decent environments, the blessings to America would be almost incalculable.

I know that a national lottery would reduce the states' incomes from gambling, but the overall pool of income would be higher. And we ought not forget that most states have never moved to equalize schooling for their poor and rich kids. Only the federal government is likely to do that.

I know that a lottery player is more likely to be struck by lightning than to win a multimillion-dollar jackpot. But so what? The odds are equally, or more, absurd in some of the sweepstakes schemes touted on television.

The people pay for a peek at a rusty pot at the end of a rainbow because they want to, which is why a national commission reported in 1976, after three years of study, that gambling was ''inevitable'' in America.

I don't know that a national lottery is inevitable. I've simply decided that it is desirable because the social benefits it could bring are much greater than any social ills that might attend it.