PANAMA CITY, JULY 9 -- A campaign by the top military officer, Gen. Manuel Antonio Noriega, to shore up his embattled political position by stirring Panamanians' anti-American spirits appears to have fallen flat.

A June 26 resolution by the U.S. Senate calling for Noriega to step down pending an independent investigation into accusations against him sparked a two-week round of pro- and anti-Noriega disturbances. Supporters of Noriega, the power behind the government here, accused the United States of intervention, a charge usually guaranteed to anger Panamanians still resentful of the 70-year history of U.S. control of the Panama Canal.

But the view heard consistently from Panamanians in capital city streets is that the crisis here is a power struggle between Noriega and his local opponents, with Washington playing only a secondary role.

Reflecting that consensus, a communique issued this week by the Roman Catholic bishops conference said, "As Panamanians, we sharply reject any foreign intervention in our affairs of state. But we believe that nationalist sentiments should not be exploited to distract us and make us forget the origins of this crisis."

On Tuesday night, President Eric Arturo Delvalle issued a surprise decree prohibiting all public protests. The ban canceled a massive anti-American demonstration by progovernment forces scheduled for today. Noriega's supporters were frustrated, not because they missed a chance to chastise the United States, but because they had hoped to prove the force of their numbers against the opposition.

The opposition National Civic Crusade, made up of business and professional groups, said it will defy Delvalle's ban and go ahead with a major anti-Noriega rally Friday, setting the stage for a potentially explosive showdown between the Panamanian Defense Forces and the opposition.

The government tonight ordered all schools and public offices to close all day Friday and said the banks would close at 11 a.m. The communique said authorities had uncovered a plot by "extremist groups" to overthrow the government.

The Senate resolution, which echoed opposition demands, at first hurt Noriega's adversaries by identifying them as allies of Washington. But as the days wore on, a growing number of Panamanians expressed private appreciation for its call for a full airing of charges of murder and election-rigging leveled against Noriega by his former second-in-command, Col. Roberto Diaz Herrera.

One Panamanian group was strengthened in its unity behind Noriega by the Senate action: the 20,000-troop defense forces. A top military officer, who spoke on condition of anonymity, said the officer corps views the resolution as "political violence" against Panamanian sovereignty.

Noriega's jousts with the United States date to mid-June when a former ambassador to Washington, Gabriel Lewis, tried unsuccessfully to mediate between the opposition and the armed forces. When the effort brought him threats from top military officers, Lewis fled to Washington and lobbied effectively for a strong Senate resolution.

Noriega's forces accused Lewis of conspiring on behalf of unnamed "ultra-conservative forces" in the United States to overthrow Noriega and Delvalle and revoke the 1977 treaties turning over the Panama Canal to this nation by the year 2000. In recent weeks, the attorney general has been questioning an ever wider circle of Noriega opponents, and even some surprised government supporters, accused of involvement in the alleged plot.

The U.S. Embassy's deputy chief of mission, John Maisto, was described in the Noriega-controlled newspapers this week as the "intellectual author" of the plot. His face is emblazoned on government posters all over town with a swastika imprinted on it. News of the alleged conspiracy, dismissed as fantasy by many Panamanians, is widely believed among followers of the defense forces' Democratic Revolutionary Party.

Noriega met here June 24 with Nicaragua's leftist President Daniel Ortega to discuss regional peace issues. The visit was seen at the time as a jab at the Reagan administration, which seeks Ortega's overthrow.

On June 30, about 5,000 Democratic Revolutionary Party militants attacked the U.S. Embassy with rocks and bottles. It was a relatively small group in a nation where anti-U.S. marches once drew tens of thousands.

In an interview Tuesday, Foreign Minister Jorge Abadia distanced the government from the anti-U.S. line, calling the embassy attack "lamentable" and promising to pay for the damage.

Abadia took pains to distinguish between the Senate and the administration, which he argued has not lessened its support for Noriega. He rejected as infantile the notion that the Nicaraguan president's trip was intended as an affront to Washington.

But as one cautious Democratic Revolutionary Party legislator, Alfredo Oranges, said this week, "We have deep nationalist sentiments, but we prefer to keep cordial relations with the United States."