Three referendums were held in Switzerland during 1919.[1] The first two were held on 4 May on amending the constitution to add article 24ter on shipping, and on a constitutional amendment to impose a war tax.[1] Both proposals were approved by a majority of voters and cantons.[1] The third was held on 10 August on temporary amendments to article 73 of the constitution, and was also approved in spite of low turnout.[1] 
  Background
 All three referendums were mandatory referendums,[1] which required a double majority; a majority of the popular vote and majority of the cantons.[2] The decision of each canton was based on the vote in that canton.[2] Full cantons counted as one vote, whilst half cantons counted as half.[2] 
 Results
 Constitutional amendment on shipping
   | Choice  |  Popular vote  |  Cantons  | 
  | Votes  |  %  |  Full  |  Half  |  Total  | 
  | For |  399,131 |  83.6 |  19 |  6 |  22  | 
  | Against |  78,260 |  16.4 |  0 |  0 |  0  | 
  | Blank votes |  19,329 |  – |  – |  – |  –  | 
  | Invalid votes |  8,401 |  – |  – |  – |  –  | 
  | Total |  505,121 |  100 |  19 |  6 |  22  | 
  | Registered voters/turnout |  937,257 |  53.9 |  – |  – |  –  | 
  | Source: Nohlen & Stöver  | 
 Constitutional amendment on a war tax
   | Choice  |  Popular vote  |  Cantons  | 
  | Votes  |  %  |  Full  |  Half  |  Total  | 
  | For |  307,528 |  65.1 |  17 |  6 |  20  | 
  | Against |  165,119 |  34.9 |  2 |  0 |  2  | 
  | Blank votes |  20,920 |  – |  – |  – |  –  | 
  | Invalid votes |  10,347 |  – |  – |  – |  –  | 
  | Total |  503,914 |  100 |  19 |  6 |  22  | 
  | Registered voters/turnout |  937,257 |  53.8 |  – |  – |  –  | 
  | Source: Nohlen & Stöver  | 
 Temporary amendment of article 73
   | Choice  |  Popular vote  |  Cantons  | 
  | Votes  |  %  |  Full  |  Half  |  Total  | 
  | For |  200,008 |  71.6 |  19 |  5 |  21.5  | 
  | Against |  79,369 |  28.4 |  0 |  1 |  0.5  | 
  | Blank votes |  19,708 |  – |  – |  – |  –  | 
  | Invalid votes |  6,710 |  – |  – |  – |  –  | 
  | Total |  305,795 |  100 |  19 |  6 |  22  | 
  | Registered voters/turnout |  931,523 |  32.8 |  – |  – |  –  | 
  | Source: Nohlen & Stöver  | 
 References
   - ^ a b c d e Dieter Nohlen & Philip Stöver (2010) Elections in Europe: A data handbook, p1907 ISBN 9783832956097 
  - ^ a b c Nohlen & Stöver, p1891