| A resident individual is allowed a credit against the tax  | 
| otherwise due under this Part, excluding the tax imposed by  | 
| section 5203-A, for the amount of income tax imposed on that  | 
| individual for the taxable year by another state of the United  | 
| States, a political subdivision of any such state, the District  | 
| of Columbia or any political subdivision of a foreign country  | 
| that is analogous to a state of the United States with respect to  | 
| income subject to tax under this Part that is derived from  | 
sources in that taxing jurisdiction also subject to tax under  | 
this Part.  In determining whether income is derived from sources  | 
| in another jurisdiction, the assessor may not employ the law of  | 
| the other jurisdiction but shall instead assume that a statute  | 
| equivalent to section 5142 applies in that jurisdiction.  The  | 
| credit, for any of the specified taxing jurisdictions, may not  | 
| exceed the proportion of the tax otherwise due under this Part,  | 
| excluding the tax imposed by section 5203-A, that the amount of  | 
| the taxpayer's Maine adjusted gross income derived from sources  | 
| in that taxing jurisdiction bears to the taxpayer's entire Maine  | 
adjusted gross income; provided except that, when a credit is  | 
| claimed for taxes paid to both a state and a political  | 
| subdivision of a state, the total credit allowable for those  | 
| taxes does not exceed the proportion of the tax otherwise due  | 
| under this Part, excluding the tax imposed by section 5203-A,  | 
| that the amount of the taxpayer's Maine adjusted gross income  | 
| derived from sources in the other state bears to the taxpayer's  | 
| entire Maine adjusted gross income. |