How did the All-Russian Congress of Soviets lose power?

According to wikipedia:

"For the earlier portion of its life, the Congress was a democratic body. Over Russia there were hundreds of soviets, democratic local governing bodies in which the surrounding population could participate. The soviets elected the delegates to the Congress, and then in turn the Congress held the national authority, making the highest decisions. There were several political parties represented in the various sessions of the Congress, each of which fought for increasing their own influence in the soviets. However, as the civil war progressed, the soviets' authority was progressively reduced, with the rise to power of Stalinism effectively cementing this situation[1] and decisively turning the Congress into a rubber-stamp parliament."

How exactly did this happen? What was the justification for this happening?

oneday wrote:

How exactly did this happen?

A lack of unity among the different parties involved both ideologically and practically was a big problem especially during war time. Many members of non-Bolshevik socialist parties stood in direct contradiction to the vision the Bolsheviks had for a Soviet socialist future; and as a result led to many parties disbanding, assimilating themselves into the Bolshevik party, splitting into pro and anti Bolshevik camps, while others were annihilated when they allied with the whites against the Bolsheviks. The multi-party system disappeared with the victory of the Reds over the Whites.

Nevertheless the Congress of Soviets retained its function as the highest legislative body in the Soviet Union under another name: The Supreme Soviet of the Soviet Union.

oneday wrote:

What was the justification for this happening?

Well I guess that's something everyone has to decide for themselves. For me it was when the combined forces of the capitalist bastards invaded our Socialist Motherland when it was still in the womb. A reminder of what the combined might of the foreign capitalist military intervention by western estimates consisted of:

70,000 Japanese in Siberia

60,000 Czechoslovak legionaries in Siberia

23,351 Greeks in the Crimea, Odessa and Kherson

17,000 Americans in the Arkhangelsk and Vladivostok regions

11,500 Estonians in northwestern Russia

6,000 French and British troops in Arkhangelsk, Vladivostok, Odessa, and the Caucasus

2,500 Italians in the Arkhangelsk region and Siberia

2,300 Chinese in the Vladivostok region

1,500 Australians in the Arkhangelsk region

1,000 Canadians in the Caucasus