The difference between individual and collective approaches may be more formal than real. The individual approach suggests that the two houses treat each amendment in isolation from the others and that they dispose of it for themselves and regardless of how they have already rejected the other amendments or how they expect to give them up. On the other hand, the collective approach suggests that both houses act in relation to all the others with each change, so the way they sell a change very well can be influenced by the agreements they have made or expect to make regarding the others. In practice, however, the difference between the two approaches is not so clear. Just because the individual approach requires both houses to sell an amendment before they accept the next one does not mean that members of both houses have not already discussed formally or informally. Indeed, they may very well have concluded agreements – agreements that Members do not want to violate, even if they are not enforceable under the rules of the two courts – what measures they intend to take with regard to each of the amendments.  On 22 November 2009, a referendum was held in Romania on the establishment of a single parliament to replace the current bicameral parliament. Turnout was 50.95%, with 77.78% of the “yes” votes voting in favour of a unicameral parliament.  This referendum had an advisory role and therefore required a private member`s initiative and another referendum to ratify the proposed new amendments. In Washington, on the other hand, the collective approach to reaching an agreement (i.e., the use of a conference committee) was not an alternative that occurs when the individual approach has failed. Instead, the collective approach of the US Congress was essentially an alternative to the exchange of positions and proposals between the two houses.
33. In a number of bicameral parliaments, the second chambers play little or no role in foreign policy. In these countries, Ireland being a good example, the ratification of the international treaty is the sole responsibility of the House of Commons (Art. 29 (5), Constitution of Ireland, 1937 (as amended on 4 October 2013) (Ir)). In some other countries, both chambers participate in the ratification of international treaties, but the last word is often left to the lower chamber. This is the case of Spain, where the Senate and the Congress participate in the ratification of most international treaties, in particular those of a military, political, human rights nature and those involving financial commitments for the Ministry of Finance (section 94, Constitution of the Kingdom of Spain: 6 December 1978 (in the version of 27 September 2011) (Spain)). If a contract is not approved by both chambers, it is necessary to create a joint commission composed of members of both chambers in order to find a compromise accepted by both chambers (Andreu 891). If the Committee does not resolve the difference, congressional decision takes precedence. In Russia, international treaties ratified by the State Duma, the House of Commons, must be examined by the Federal Council (Art. 106, Constitution of the Russian Federation: 12. December 1993 (in its version of 21 July 2014) (Russ)).
In the German, Indian and Pakistani systems, the upper houses (Bundesrat, Rajya Sabha and Senate) are even more closely linked to the federal system and are appointed or elected directly by the governments or legislators of any German or Indian state or province of Pakistan. This was also the case in the United States before the passage of the Seventeenth Amendment to the Constitution. Because of this connection with the executive, the doctrine of German law does not formally treat the Bundesrat as the second chamber of a bicameral system. . . .