"There are those who have given their lives for liberty.Help us to defend it," reads the gray-and-white campaign poster on a wall across from this northern Italian city's Arena Park.

The somber poster bears a photo of the ruling Christian Democratic Party's slain leader, Aldo Moro, over a picture of a sidewalk with the chalked outlines of a body surrounded by spent cartridges.

With national elections scheduled June 3, the Christian Democrats are emphasizing two themes: antiterrorism and anticommunism. Yet they are careful not to place the blame for Italy's rampant political terrorism directly on the doorstep of their major opponent, the Communist Party.

Nonetheless, say the Christian Democrats, the growing political violence has its roots not in disaffection caused by 30 years of ineffective Christian Democratic rule, but in angry leftist propaganda and increasing Communist pressure for a significant governing role.

Whatever the causes, the party leadership thinks the Christian Democrats are likely to gain politically from the violence. Four days after the bullet-ridden body of former premier Moro was found in Rome a year ago, Christian Democrats scored gains in local elections throughout Italy.

Party strategists think the terrorist acts that began with the start of the national campaign earlier this month will again yield dividends at the polls at the expense of the Communists.

Recent polls indicate that the Christian Democrats are likely to gain two to four percentage points in the national vote, up from the 38.8 percent they polled in the 1976 election. The Communists are expected to poll 31 or 32 percent, down from 34.4 percent.

"People feel we can give them the greater security, the better trained and stronger police force and the acceleration of judicial procedures that they want," said Sen. Luigi Gui, the former defense minister who heads the Christian Democrats' Padua ticket.

The party's themes of antiterrorism and anticommunism were evident during a memorial anniversary mass for Moro May 9 at the 11th century monastery of Praglia.

After the service, Sen. Pietro Schiano told the emotional audience that Moro's sacrifice should not be in vain. He said today's terrorism was the fruit of the Communists' past rhetoric of violence and demands they made in the 1950s for a disarmed police force.

"Moro would have been the first to abhor the idea of giving the Communists real power," Schiano said after the ceremony.

While making it clear that the Communists were now opposed to violence, he criticized them for their decision to block new laws designed to improve police efficiency - rhetoric that hits home in this city of 250,000 that experienced 76 terrorist acts between January and April.

The violence has left deep scars on Padua.

'People are scared, afraid of getting involved, afraid of getting hurt," observed Nino Berruti, editor of the local tabloid, II Mattino.

Christian Democratic officials and party office elsewhere in Italy have been the targets of repeated terrorist attacks in recent weeks. In the violence-clouded climate, party leaders are virtually unanimous in their rejection of sharing power with the Communists at the national level.

"We will never govern with the Communists," Sen. Gui thundered amid enthusiastic applause at a rally opening his Padua campaign.

Yet despite this near total agreement on the question of the "historic compromise" - sharing power with the Communists - Christian Democrats are split on the degree to which the party should cooperate with the left.

Some, like the Padua party secretary, Aldo Bottin, feel that two parties so different in ideology cannot cooperate successfully, while others believe a degree of cooperation is necessary.

Padua's Communists say the Christian Democrats do not take terrorism seriously.

"Playing up the drama of terrorism rather than focusing on its cause certainly makes electioneering a whole lot easier, "a Communist here said.

After attending the Gui rally, a young lawyer from Padua said, "This country has serious problems and yet the Christian Democrats are still playing the same old, boring anticommunists music."