From CNN.

Maine’s US Senate race is shaping up to be one of the most critical battlegrounds of the midterms, with control of the chamber potentially on the line. Democrats are aiming to unseat Republican incumbent Susan Collins, while a competitive Democratic primary is heating up between two-term Governor Janet Mills and newcomer Graham Platner. CNN’s Manu Raju reports. For more of Manu’s reporting from Maine, watch "Inside Politics Sunday with Manu Raju" on Sunday at 8a and 11a ET on CNN.