What is the level of evidence necessary to arrest a person

Probably Cause which would render reasonable belief in guilt

Explanation:

Police need probably cause to arrest someone or to obtain an arrest warrant from a judge.  Probably cause is not just suspicion.  There has to be facts or information that would create a reasonable belief that the person may be guilty.  The facts or information does not have to prove this beyond a reasonable doubt.  Without an arrest warrant from a judge, the police must show that the arrest was immediately necessary.

a nurse can ask a member of congress to sponsor a bill that she/he finds important

explanation:

magic