Final answer:
The rhetorical strategy used in the sentence is an appeal to ethos, establishing credibility through 'informed sources'. It might also involve logos, as it presents a claim that seems logical. This technique aims to persuade by implying authority, rather than relying solely on rational arguments.
Step-by-step explanation:
The rhetorical strategy used in the sentence "Informed sources confirm that the President colluded with Russia" is an appeal to ethos, as it attempts to establish credibility by referring to 'informed sources.' This strategy suggests authority and reliability without necessarily providing evidence, thereby building trust with the reader through the implication of insider knowledge.
The writer may also be employing logos, as the statement appears to be a factual claim that could persuade readers who value logical evidence.
This approach can be effective but also potentially misleading if the sources are not named, and it keeps the focus away from a purely logical argument. Writers often use such strategies, along with techniques like bandwagon or ad hominem, to persuade readers through means other than rational arguments. This reflects an intent to meet or challenge rhetorical situation norms in order to influence the reader's perspective.