Here's a guide on what to look for as the election returns start to come in Tuesday night.

The first thing to remember is that the running total of popular votes that the networks feature prominently is meaningless.

The only number that really matters is 270 _ the number of electoral votes needed to win the White House.

It could be clear early in the evening _ perhaps after the polls close at 8 p.m. EST in 19 states _ that Republican George Bush will be the 41st president of the United States

If Democrat Michael Dukakis is going to pull a miracle, he'll have to win every state in which he has a reasonable chance. Dukakis has little or no chance to win many states in the South, Plains and Rocky Mountains.

If Dukakis is to win, he'll have to carry California, where the polls don't close until 11 p.m. EST. Bush could nail down a victory much earlier.

The first presidential tip-off will come from Kentucky, where the polls close at 6 p.m. EST. If Dukakis should win there, then the election may not be a sure thing for Bush. That doesn't mean Dukakis is on his way to the White House if he upsets Bush in Kentucky, but it would be a sign he's running stronger than expected.

The ABC, NBC and CBS evening news programs will be the next indication. The networks interview voters exiting polling places in key precints throughout the day all over the country. Network officials have pledged not to announce the results of their polling in a state until the polls close in that state. But they'll know in the late afternoon what the likely results will be.

The key to understanding what the networks know is listening to the code words they use on those newscasts.

If the anchors say it's going to be a good night for Bush, you can bet their data show Bush has won. If they say it's close, then maybe it's closer than expected, but it's unlikely an upset is in the making. If they say it's very close, then that could mean you're in for a long night.

The thing to remember about exit polls is that despite politicians' criticisms of them, they are almost always on target. There is one exception: California, where the Republicans put together a massive absentee-ballot operation and the exit polls understate GOP strength. A dead heat in California exit polls would mean a likely Republican victory.

Six states close their polls at 7 p.m. EST, and all are locks for Bush with the exception of Vermont, where the race is thought to be quite close.

If Vermont goes for Dukakis, or if any of the other five _ Florida, Indiana, Georgia, South Carolina or Virginia _ are close, then it might not be a sure Bush win.

At 7:30 p.m. EST you'll get an indication of whether it's going to be a Bush landslide. If West Virginia, traditionally a Democratic state, but where polls until recently had the Republican ahead, goes for Bush, it's all over. If Dukakis holds onto it, it doesn't mean much.

Also at 7:30, the polls close in Ohio, a state in which Bush is expected to win. If he doesn't, it's possible to put together a scenario in which Dukakis wins the presidency.