In today’s renaissance of socialism, many old debates among the left have reemerged. Publications such as Left Voice, Cosmonaut, Jacobin, and Regeneration have rekindled the central dispute over reform vs. revolution. However, to more clearly understand the roots of this debate, it is important to understand the place of Luxemburg and Kautsky in the Second International.
By Peaceful Means
In the Second Communist International — and particularly in the Social Democratic Party of Germany (SPD) — there emerged roughly four general views. Evolutionary socialism developed as a right tendency. Championed by prominent SPD theoretician Eduard Bernstein, it was characterized by belief in a slow transition to socialism through parliamentary reform. Another tendency was that of revolutionary Marxists who supported the overthrow of bourgeois states and their replacement with a republic of workers’ councils (Soviets). Some of the most well known historical figures of this tendency were Rosa Luxemburg, Leon Trotsky, and V.I. Lenin.
On the far-left of revolutionary socialism was what Lenin called “Left-wing communism”, characterized by a rejection of parliamentary tactics and an emphasis on building workers councils. A champion of this tendency was the Italian Marxist Amadio Bordiga. The middle ground of this debate is the fourth of these tendencies, the Kautsky perspective, now at the center of debates about 21st Century Socialism. Kautsky was a revolutionary Marxist in the SPD, a leader in the Second International, and a major influence on Lenin and the Bolshevik Party. Though Kautsky was known as one of the great Marxists of his time, his views shifted later in life, particularly in the face of the Spartacist Uprisings, the soviet revolution in Germany which lasted from 1918-1919. Kautsky sought a middle ground between evolutionary socialism and revolutionary socialism, one in which socialist transformation would follow fast upon the emergence of working class power and parliamentary majority, not after long decades of reform.
Infamous for his betrayal of the 1918-19 German Revolution, Kautsky urged the Spartacus League to lay down their arms and wait until socialists were in clear control of parliament, declaring “The ‘Spartacides’ should be rather more careful in their method of indiscriminately applying templates drawn from the past, and from other countries, to the Germany of today. Just recently they tremendously failed with the call they blunderingly took from Russia: ‘All power to the workers’ and soldiers’ councils’. The current revolution in Germany has its own laws.”  Kautsky’s views, though detrimental to the German Revolution, were not entirely wrong. Marx clearly allowed for Kautsky’s idea of revolution:
In our midst there has been formed a group advocating the workers’ abstention from political action. We have considered it our duty to declare how dangerous and fatal for our cause such principles appear to be. Someday the worker must seize political power in order to build up the new organization of labor; he must overthrow the old politics which sustain the old institutions, if he is not to lose Heaven on Earth, like the old Christians who neglected and despised politics. But we have not asserted that the ways to achieve that goal are everywhere the same. You know that the institutions, mores, and traditions of various countries must be taken into consideration, and we do not deny that there are countries — such as America, England, and if I were more familiar with your institutions, I would perhaps also add Holland — where the workers can attain their goal by peaceful means. This being the case, we must also recognize the fact that in most countries on the Continent the lever of our revolution must be force; it is force to which we must some day appeal in order to erect the rule of labor. 
Kautsky’s mistake was not in recognizing the possibility of socialism after a parliamentary victory, but in refusing to allow for any other path. As history shows in the examples of Czechoslovakia (1948) and Yugolsavia (1942), socialist republics are sometimes established after workers win parliamentary majorities, but these appear to be exceptions, not the rule.
Neither was Kautsky mistaken in his view of liberal parties. Despite Eric Blanc’s Position in Jacobin Magazine of Kautskyism , Kautsky never advocated for working with or inside liberal, pro-capitalist parties. Instead, he actively fought for their defeat.
By Any Means
When looking for historical guidance on the question of reform vs revolution, Rosa Luxemburg may offer more insight than Kautsky. In Reform or Revolution — a polemic against Bernstein — she states:
Can the Social-Democracy be against reforms? Can we contrapose the social revolution, the transformation of the existing order, our final goal, to social reforms? Certainly not. The daily struggle for reforms, for the amelioration of the condition of the workers within the framework of the existing social order, and for democratic institutions, offers to the Social-Democracy the only means of engaging in the proletarian class war and working in the direction of the final goal – the conquest of political power and the suppression of wage labour. Between social reforms and revolution there exists for the Social Democracy an indissoluble tie. The struggle for reforms is its means; the social revolution, its aim. 
Luxemburg also railed against Kautsky for his “nothing but parliamentarism” when she advocated an SPD push for mass strike. Does this imply Luxemburg opposed electoral battles? No, Luxemburg was a staunch supporter of electoral battles in parliament as a means to fight for reform, to agitate, and to push the socialist movement forward. Luxemburg had a balanced view; she understood the need for socialist party leadership of the working class in the political arena of the bourgeois state, but she also saw the necessity — during the right historical moment — of dissolving and replacing the bourgeois state with a soviet republic. Luxemburg did not view parliament as the only arena of working class struggle, but rather one of many. In The Mass Strike, she discusses the differing political expressions of the working class during non-revolutionary and revolutionary periods:
On the other hand the political struggle is not directed by the masses themselves in a direct action, but in correspondence with the form of the bourgeois state, in a representative fashion, by the presence of legislative representation. As soon as a period of revolutionary struggle commences… the breaking up the economic struggle into many parts, as well as the indirect parliamentary form of the political struggle ceases; in a revolutionary mass action the political struggle ceases; in a revolutionary mass action the political and economic struggle are one, and the artificial boundary between trade union and social democracy as two separate, wholly independent forms of the labour movement, is simply swept away. But what finds concrete expression in the revolutionary mass movement finds expression also in the parliamentary period as an actual state of affairs. 
Understanding the differences between socialist activity before and during revolutionary crisis is essential to mapping revolutionary strategy today; the strategies necessarily differ dramatically. During normal periods, in the absence of revolutionary crisis, parliamentary battles are of primary importance. Lenin, one of Luxemburg’s greatest allies in the Second International, echoes the same argument when debating Bordiga and the left-wing communist faction, saying “Parliament is a product of historical development which one cannot abolish from the world until one is strong enough to scatter the bourgeois parliament. Only if one is a member of parliament can one combat bourgeois society and parliamentarism from the given historical standpoint. The same means that is applied by the bourgeoisie in smuggle must also be applied by the proletariat, naturally with quite different ends .”
By the Means Necessary for Today’s Struggle
History shows the revolutionary path that corresponds closely to conditions today. The US working class lacks political expression in the state through an independent socialist party. Its political expression is suborned by the progressive wing of the Democratic Party. Since many self-described democratic socialists of the Democratic Party have supported war budgets and military interventions, the political intentions of the working class are integrated neatly with liberal imperialism. At best, the working class achieves incremental reforms that pose no real threat to capitalism. The correct path for the working class during this non-revolutionary era is the formation of an independent party of and for the working class. The most advanced layers of the working class must unite around a party that struggles for social reform as a means to the objective of social revolution.
 Kautsky, K. Driving The Revolution Forward. https://www.marxists.org/archive/kautsky/1918/12/forward.html
 Marx, K. La Liberte Speech. https://www.marxists.org/archive/marx/works/1872/09/08.htm
 Blanc, E. Karl Kautsky As Architech of the Russian Revolution. https://www.jacobinmag.com/2019/06/karl-kautsky-vladimir-lenin-russian-revolution
 Luxemburg, R. Reform or Revolution. https://www.marxists.org/archive/luxemburg/1900/reform-revolution/index.htm
 Luxemburg, R. The Mass Strike. https://www.marxists.org/archive/luxemburg/1906/mass-strike/ch08.htm
 Evening Session August 2nd, Meeting of the Second Congress of the Communist International. https://www.marxists.org/history/international/comintern/2nd-congress/ch08a.htm