Political candidates’ speeches are loaded with promises and with expressions of good intention, but one must not forget that the politicians’ purpose in giving these speeches is to get themselves elected.
Evidence
Political candidates’ speeches are loaded with promises and with expressions of good intention.
But one must not forget that the politicians’ purpose in giving these speeches is to get themselves elected.
Conclusion
Clearly, then, these speeches are selfishly motivated and the promises made in them are unreliable.
Evaluate
This is an ad hominem attack. Just because politicians are motivated to win reelection does not mean that their promises are unreliable.