First, and most importantly, the only known bias in the TIF is the omission of secret agreements that, if published, could threaten national security. Footnote 79 However, since these secret agreements are by definition not known to the public, they are likely to also be absent from other databases. Second, the TIF agreements all follow an understandable selection process: these are agreements that are submitted to Congress in accordance with the case law and are considered by the Department of Foreign Affairs to be in force. Combining these agreements with other databases can lead to unknown selection distortions that compromise the interpretation of the results. Third, the TIF uses its own index system, so that TIF agreements cannot be easily compared to agreements from other sources. Fourth, previous attempts to combine datasets have resulted in a much smaller number of agreements than is included in the dataset used here. Footnote 80 For these reasons, this article suggests that a dataset based on TIF is preferable to a combination of different sources. 1.A contract requires a two-thirds majority in the Senate, while an executive agreement does not. 2.A The contract is a formal agreement, while an executive agreement is not as formal as a contract. 3.A treaty is forwarded to successive presidents, while an executive agreement must be renegotiated each time.
4.An executive agreement is of two types, while a contract is not. 5.A President may appoint an executive agreement, but not a contract. 6.Es gives much more executive agreements than contracts. The analysis sorts the agreements according to their lifespan and assumes that x-quantil is an exclusive executive agreement, x ∈ [0, 0.1]. For example, x -0.03 assumes that the 3% of the least durable agreements are one-off executive agreements. It then omits these agreements from the analysis, executes the preferred model (5) and counts the estimated coefficient on the contractual indicator and its standard defects. Keep in mind that the assumption that the least durable agreements are exclusive executive agreements is extremely restrictive. In fact, it is much more likely that some unique executive agreements will survive the agreements between Congress and the executive branch. This approach can therefore be expected to distort the sustainability of congressional executive agreements, making it more difficult to differentiate between tenure of contracts and executive agreements. While it can be shown that even in these restrictive assumptions, contracts are viable, this is particularly strong evidence of an increase in the lifespan of contracts. To answer this question, scientists have made several hypotheses about the current role of the treaty.