With Friends Like These: There are millions of Americans who apparently number Jimmy Carter and Tip O'Neill among their most valued political assets, but the Speaker of the House and the former president can be forgiven if they are underwhelmed and don't mist up over the honor. Those millions of Americans are called Republicans.

Tomorrow, the GOP begins a $1.7 million, six-week national television campaign in 56 major media markets blaming Carter and O'Neill for inflation, unemployment, recession, nearly everything but the heartbreak of psoriasis.

Carter will be played by an actor from Waco, Tex.; O'Neill by Edwin Steffe, the New York actor who played the same role in the GOP's 1980 commercials.

Rep. Guy Vander Jagt (R-Mich.), chairman of the Republican Congressional Campaign Committee, and GOP national chairman Richard Richards will show the Carter-O'Neill commercial and a second one that proclaims the end of inflation at a press conference in Washington.

Then they will fly to Atlanta, Chicago and Los Angeles for similar press conferences.

The Democrats, predictably, are crying foul, but fair's fair. They owe much of their modern success and what party unity they've enjoyed to Republicans Herbert Hoover and Richard Nixon.

And Jody Powell, Carter's White House press secretary, returned the favor, with a barb.

"I don't think it's exactly fair to have an actor who looks like a former president," he deadpanned. "If you did it to Ronald Reagan, you'd have to have an actor playing an actor playing a president."