The four arguments in reference to the given statement are
(i) In most democracies, elections are fought among the candidates put up by political parties. The party which wins the majority, forms the government. In a parliamentary system, the leader of the party in power becomes the Prime Minister and he appoints the other ministers.
(ii) In a democracy, a large number of similar opinions have to be grouped together to provide a direction in which policies can be formulated by the government. Political party reduces a vast multitude of opinions into a few basic positions and if it is ruling party, government accepts the line taken by it.
(iii) Political parties raise and highlight issues. Often they shape public opinion.
There are always some socio-economic and political issues at the domestic and international level. Political parties always try to tackle the issues.
(iv) The parties which play the role of opposition in the government always criticise government for its wrong policies. Opposition parties mobilise opposition to the government. Thus, political parties are rightly called the government in disguise.