Weighing East Bloc, Baltic Hopes. REPORTER'S NOTEBOOK

IT doesn't take long to feel the tension. Across the street from the Latvia Hotel, demonstrators hold up posters calling for the end of ``the Russian occupation.''

Similar cries of nationalism are heard throughout Eastern Europe, from Poles demanding the return of their free-trade union Solidarity, to angry Czechs demonstrating for Alexander Dubcek's rehabilitation, to Hungarian crowds calling for the protection of their mistreated cousins in neighboring Romania. The common denominator, whether in the Baltics or Eastern Europe, is the plea to restore national dignity and sovereignity.

But behind this similarity, the two struggles are quite different. The three nationalist Soviet republics face two explosive dilemmas unknown to the nominally independent East Europeans. First, they must decide whether to call for total independence from the Soviet Union. And second, they must decide what rights the large numbers of Russian residents should enjoy.

Beyond these obvious factors, Baltic defiance of Russian power seems fresher, more exciting than East European defiance. When the Latvian tricolor was recently raised, bystanders wept.

In contrast, a skepticism prevails in East Europe. When Solidarity first was born in 1980, many Poles recall experiencing an exhilarating sense of national rebirth. Martial law in 1981 crushed that dream. Today, as Solidarity prepares to regain its legal status, ordinary Poles refuse to raise their hopes too high.

``I'd like to be excited, to believe Solidarity will bring freedom; but I can't,'' says one Gdansk housewife. ``What really worries me is how I'm going to heat my apartment this winter.''

Ironically, this skepticism may give East Europeans a greater chance to shake off communism's shackles. Compromise colors mainstream East European thinking. In Poland and Hungary, both the opposition and the authorities talk of a controlled process of democratization. In Czechoslovakia and East Germany, the local opposition calls for dialogue, not the end of communist rule. No one wants to provoke the Soviets. Similar caution seems absent in Riga. Demonstrators talk of confrontation. In separate interviews, state president Anatoly Gorbunov and a Popular Front leader, Janis Peters, both expressed concern about growing tensions.

Mr. Peters' Popular Front calls for considerable autonomy. But he admitted that a growing number of ``impatient'' people within the movement want nothing less than total independence.

Mr. Gorbunov, a reform-minded figure in Latvia, worried that ``destabilization'' might lead Moscow to intervene militarily.

The immediate danger is an open confrontation between Russians and Latvians. On the recent Red Army Day, a large group of Russian patriots clashed with Latvians - verbally then, perhaps violently the next time.

``It's a terribly tense situation,'' says Mavrik Wulfson, another Popular Front leader. ``We must lead a politics of reason, not a politics of emotion.''

East Europeans look toward independent Finland as their model, where Soviet security interests and a democratic system coexist. Moscow officials suggest this model may be possible, if the changes do not lead to instability.

The Balts may be morally right to demand the same deal. But if they do, it could well prompt a much stronger reaction from Moscow, such as military intervention.