Social Democratic Party Annual Membership Figures

According to figures cited at the "First Convention" of March 6-9, 1900, the Social Democratic Party had added about 1000 dues paying members from the first of the year, to stand at a total of about 4,500 at the time of the Convention. [Social Democratic Herald, March 17, 1900, pg. 1]


About 3,500


About 4,500


Socialist Party of America Annual Membership Figures

The Socialist Party collected dues monthly rather than annually, using a system of membership cards and dues stamps. Under this system, stamps would be advanced in bulk to State Party organizations and Language Federations, who then sold these stamps to the membership at meetings. Members missing a previous meeting would generally buy more than one stamp at a time to pay for dues in arrears. Local and State organizations -- or Language Federations, as the case may be -- would get a share of the money for each dues stamp sold and would remit the balance of funds to the National Office.This system, borrowed from trade unions of earlier days, inevitably resulted in a fluctuation of the number of stamps sold by the National Office each month. The standard method of calculating the membership of such organizations involves the average number of stamps sold over the course of a particular quarter or year. Scholars should remain dubious of any single monthly stamp sales total being presented as indicative of a group's true membership size, as partisans of the day often did.

During the years 1901 and 1902, dues payments to the National Office from the various states were somewhat irregular in frequency and record-keeping seems to have been poor. The purported membership at the time of the 1901 Unity Convention of a round "10,000" is fanciful, although the party does seem to have approached this membership figure during the subesequent year. No hard numbers for 1902 membership are available, but the rough and round estimate may be regarded as approximately correct.

With the exception of the 1901 and 1902 estimates, which are based on material published in the Social Democratic Herald, and the figure for the first six months of 1903, which comes from Appeal to Reason no. 405 (Sept. 5, 1903), the following series of average monthly dues stamp sales per year is based upon the official statistics published annually in The American Labor Year Book by the Rand School of Social Science, a Socialist Party training school. The figures may be regarded as official and were not subject to any form of systemic falsification:



("About 4,000 at the time of the Unity Convention -- SDH of May 25, 1912, pg. 4).


- (no statistics kept: approximately 10,000 claimed in statement to party members.)


15,975—— + 59.8%


20,763 -- -- + 30.0%


23,327—— + 12.3%


26,784 ---- + 14.8%


29,270——- + 9.3%


41,751—— + 42.6%


41,470 -——0.7%


58,011—— + 39.9%


84,716—— + 46.0%


—— 118,045 --- -- + 39.3%




93,579—— - 2.5%




83,284—— + 4.9%


80,379——- - 2.5%


82,344—— + 2.4%

1919 (Q-1) 104,822

—— + 27.3%


From this a few things should be noted: (1) That the Socialist Party showed its most explosive period of growth in the years 1910-12; (2) That despite the defection of the party's Right Wing over the issue of the war, the SPA held its own in 1917-18 despite its uncompromising anti-militarist stance and the harsh government persecution related to this; (3) That the alleged "flooding" of the membership with new elements during the first quarter of 1919 was well within historical parameters of growth for the group both in terms of absolute number of members and the percentage rate of growth which the new recruits represented.

After the suspensions, expulsions, and defections ensuing from the party crisis of 1919 and its aftermath, Socialist Party membership plummeted. Figures below for the 4th quarter of 1919 and for 1920 are from Trachtenberg and Glassberg (eds.), The American Labor Year Book, 1921-1922, pg. 392; Figures for 1921-1922 from DeLeon and Fine (eds.), The American Labor Year Book, 1925, pg. 141:


1919 (Q-4)









After 1922 the SP became no less secretive than the Communist movement about its actual membership figures. Instead of releasing a membership count, which would publicize the magnitude of its implosion, the membership series (above) for the party stopped appearing in print and cumulative vote totals for Socialist candidates across the country began to be published instead. Party membership probably remained in the general vicinity of 11,000 for the remainder of the 1920s. Claimed memberships -- all very highly suspect -- of 18,000 (1924), 25,000 (1925) and "about 15,000" (1926) provide top estimates for the period.

A document which emerged in 2004 revealed for the first time hard membership figures for the first 10 months of 1927 and 1928. These figures were tabulated from a Nov. 24, 1928 report of National Executive Secretary William H. Henry to members of the National Executive Commitee (original in the collection of Bob Millar).


11,118——- xxxx


11,332—— + 1.9%

It should finally be noted that the party crisis of 1919-1921 did not have a long-term effect of "Americanizing" the SP from foreign-born members -- even after the smoke cleared from the mass purges of the Language Federations and defections, the Socialist Party retained a very high foreign language-speaking component. Some 41.6% of SP members in the first quarter of 1922 were affiliated with the party through Language Federations, according to the SP's own statistics. [See: DeLeon and Fine (eds.), The American Labor Year Book, 1923-1924, (New York: Rand School Press, 1924), pg. 125.] In short, many of the members of the Language Federations proved just as loyal to the institution of Socialist Party as their American-born comrades.

With immigration restricted and the membership aging, the SPA's Language Federations showed decline throughout the decade of the 1920s. The percentage of the SP maintaining membership through the Language Federations fell from 34.8% to 30.1% of the party between 1927 and 1928, according to figures in the report of Executive Henry cited above. The SP maintained 5 federations during these years -- Finnish, Yugoslav [Slovenian], Jewish, Italian, and Lithuanian. The component enrolled in English language branches rose by 9.3% over the same interval.

The early 1930s saw a modest comeback of the Socialist Party in terms of membership growth and influence under the leadership of Norman Thomas before the party blew apart in factional warfare in the second half of the decade:



—— approx.



—— approx.



—— approx.



—— approx.



—— approx. 



—— approx.



—— approx.




1937 (Jan.-Feb.) - 6,488



The 1929-1935 numbers above are approximates generated by multiplying the officially reported paid memberships of language federations by the reciprocal of the officially reported percentage of membership which those federation memberships represented. The 1936 and Jan.-Feb. 1937 figures are given in the report printed for delegatges to the party's 1937 Special National Convention, including both paid and dues-exempt memberships. The 1936 decline was exacerbated by the disaffiliation of the Finnish and Jewish Federations, organizations loyal to the Old Guard faction, with 1137 and 606 members, respectively.

-- Tim Davenport