Los Angeles, Aug. 17 -- The difference between the Republicans and Democrats is the difference between Rick Schroeder and Jimmy Smitts. Both actors are probably best known for baring their backsides on NYPD Blue. Mr. Schroeder talked to the Republican convention about troubled youths. Mr. Smitts talked to the Democrats about health care.

Is Dennis Franz, who has played partner to both actors onscreen, over at the Shadow Convention, talking about the budget surplus?

There are vital differences between the two parties. The Democrats favor abortion rights, more gun laws, and using the budget surplus to shore up Social Security. The Republicans oppose abortion, want no more gun control, and yearn to turn the surplus into a tax break. The parties can run a compelling campaign on those issues alone.

But after covering these two conventions, it's some of the purely superficial differences that stand out most strongly for me; and some of the similarities.

The Republicans are on time. The Democrats run behind. Republican men tend to be clean-shaven, Republican women seem to lacquer their hair. Democratic delegates, men and women, can look like they've shown up to answer a casting call for a road company of Grease.

The Democrats are Tommy Lee Jones. The Republicans are Bo Derek. The Democrats are Melissa Etheridge singing the national anthem. The Republicans are Chaka Kahn singing the closing benediction.

The Republican convention bloomed with hand painted signs for BUSH, CHENEY, and COLIN POWELL. The Democrats have more signs -- not only GORE and LIEBERMAN, but also CAROLINE (Kennedy), and HADASSAH (Lieberman). But their posters are machine-printed. This may be the difference between free enterprise Republicans who letter their own signs, and Democrats who hire union labor.

The Democrats are Caroline Kennedy. The Republicans are Nancy Reagan.

But there are similarities that are just as cutting. Both parties now routinely make use of wives and children to introduce a candidate, from Laura Bush and Lynn Cheney, to Hadassah Lieberman and Karenna Gore Schiff. It would be nice to think that someone running for office could find someone outside of their immediate family to speak in their behalf.

Both Republicans and Democrats spend a lifetime trying to get rich, but turn humble at conventions.

In Philadelphia, George Bush, the son of a president and inheritor of a fortune, presented himself as a Texas oil field roughneck, rather than a preppie and a Yalie. Last night in Los Angeles, Joe Lieberman reminisced about his father driving a bakery truck. Mr. Lieberman, who is another Yalie, did not add that his father turned that bakery business into a prosperous chain of stores.

Tommy Lee Jones, who was Al Gore's college roommate, recollected good times they spent together chasing loose cows and hunting raccoons. They must have had to track them down in Harvard Square.

By the end of this campaign, Mr. Lieberman's father may grow even poorer, Mr. Bush's recollections may grow oilier -- and Al Gore might wear a crimson-trimmed coonskin hat.