Croatia Joins Slovenia in Secession : Yugoslavia: Republic’s Parliament declares all federal laws void. The president says it will fight to defend itself.

The republic of Croatia on Thursday joined Slovenia’s move to secede from Yugoslavia, stepping up the pressure at crisis talks scheduled for today in Sarajevo that seek an alternative to a violent national breakup.

The Croatian Parliament nullified all federal laws in the republic and declared that federal officials in Belgrade have no right to proclaim a state of emergency without Croatia’s consent.

In addition, lawmakers in Zagreb bestowed immunity from arrest on Croatian government ministers.

Although the legislative moves are intended to shield Croatia from any military or federal intervention to prevent its secession, they are likely to anger those same forces, from which an armed intrusion is feared.

The federal army, under the command of Communist officers who are predominantly Serbs, has been threatening to arrest Croatian Defense Minister Martin Spegelj for allegedly plotting an armed rebellion.

Spegelj has denied the charge, which stems from a controversial videotape produced by the army purporting to show him planning the assassination of federal officers. Croatian President Franjo Tudjman has vowed to protect Spegelj from what he has described as trumped-up charges.

An army arrest warrant issued last Friday sharpened tensions between Serbs and Croats, the bitter ethnic rivals who constitute Yugoslavia’s largest nationalities.

Tudjman has warned that Croatia will defend its new democratic leadership with armed force if necessary, so an attempt to arrest Spegelj could provide the spark that ignites civil war.

Serbia is still ruled by hard-line Communists, but Croatia and Slovenia last spring voted in leaders who have promised to transform their republics into democratic states with market economies and stronger ties to the West.

Tudjman’s government accuses the federal army of seeking a pretext to invade Croatia to install a regime loyal to communism.

Only one of Yugoslavia’s six republics--Bosnia-Hercegovina--has been contributing its full share of funds to support the federal government. The resulting budget crisis has been holding up paychecks for federal workers, including army officers.

Slovenia, the most affluent republic, overwhelmingly passed secession legislation Wednesday, annulling federal authority in this northernmost republic and proposing a formal act to dissolve the statehood of Yugoslavia.

That proposal is expected to add another strain on negotiations resuming today in the Bosnian capital of Sarajevo, where federal and republic leaders will make a fifth stab at resolving their differences peacefully.

“The Yugoslav summit in Sarajevo should open with the adoption of rules of the game which should make the existing alliance invalid until further notice,” the Zagreb daily Vjesnik suggested Thursday.

Four previous sessions of the talks aimed at holding the federation together while the republics renegotiate their relations have broken down without agreement.

Slovenia and Croatia had sought a looser Yugoslav alliance that would ease the burden of subsidizing Serbia, Macedonia and Montenegro, where per capita income is half that of the northern republics.

However, Serbia insisted on strong central rule, prompting the north to take the first steps toward secession.

By virtue of being the largest ethnic group, with 9 million of Yugoslavia’s 24 million citizens, Serbia has always exercised the most power within the federation, which was created in 1918.