The potential for tactical voting is large. Receiving only one vote, the rational voter must only vote for a candidate that has a chance of winning, but will not win by too great a margin. This also creates a gigantic opportunity for tactical nominations, with parties nominating candidates similar to their opponents' candidates in order to split the vote.
SNTV also results in complicated intra-party dynamics because in a SNTV system, a candidate must not only run against candidates from the other party, he or she must also run against candidates from their own party.
Because running on issues may lead to a situation in which a candidate becomes too popular and therefore steals votes away from other allied candidates, it has been argued that SNTV encourages legislators to join factions which consist of patron-client relationships in which a powerful legislator can apportion votes to his or her supporters. It has been argued that many of the characteristics of the Kuomintang in Taiwan and the Liberal Democratic Party of Japan arise because of this.
In addition, parties must ensure that their supporters evenly distribute their votes among the party's candidates. In Taiwan, the Kuomintang does this by sending members a letter telling them which candidate to vote for. With the Democratic Progressive Party, vote sharing is done informally, as members of a family or small group will coordinate their votes. The New Party had a surprisingly effective system by asking party supporters to vote for the candidate that corresponded to their birthdate.
Iraq's interim constitution, Article 32(B) mandates SNTV for the election of the president of the National Assembly. The three highest candidates are elected respectively president, first and second deputy president of the assembly.
A system that so drastically favours horse-trading and gives rise to unexpected results does not obviously recommend itself to a nation with limited experience of parliamentary wheeling and dealing and a pronounced tendency to blame adverse results on conspiracy.