A: Tom is very nervous. He is going to run for the chairman.
B: Let's have us at his back.
A: All right. We'll talk to him tonight.
have someone at one’s back：有某的支持，得到某人的支持
e.g. If you make this decision you will certainly have the President at your back.
e.g. Mike has the manager at his back in his argument with the customer because he is right.
e.g. The candidate has a large number of people at his back.
e.g. Simon knows that he has the head of the Department at his back.
1. run for：竞选
e。g。 I'm planning to run for the school board。
e.g. Five candidates want to run for the presidency this year.
2. at one’s back：得到支持
e.g. There must be someone at his back.
e。g。 He was a benefactor with collective society at his back。
e.g. The boy has done many evil deeds, but he does not fear anything with his father at his back.