(1) Authorized purposes; two-thirds limitation. The General Assembly shall have no power to contract debts secured by a pledge of the faith and credit of the State, unless approved by a majority of the qualified voters of the State who vote thereon, except for the following purposes:

  (a) to fund or refund a valid existing debt;

  (b) to supply an unforeseen deficiency in the revenue;

  (c) to borrow in anticipation of the collection of taxes due and payable within the current fiscal year to an amount not exceeding 50 per cent of such taxes;

  (d) to suppress riots or insurrections, or to repel invasions;

  (e) to meet emergencies immediately threatening the public health or safety, as conclusively determined in writing by the Governor;

  (f) for any other lawful purpose, to the extent of two-thirds of the amount by which the State's outstanding indebtedness shall have been reduced during the next preceding biennium.

  (2) Gift or loan of credit regulated. The General Assembly shall have no power to give or lend the credit of the State in aid of any person, association, or corporation, except a corporation in which the State has a controlling interest, unless the subject is submitted to a direct vote of the people of the State, and is approved by a majority of the qualified voters who vote thereon.

  (3) Definitions. A debt is incurred within the meaning of this Section when the State borrows money. A pledge of the faith and credit within the meaning of this Section is a pledge of the taxing power. A loan of credit within the meaning of this Section occurs when the State exchanges its obligations with or in any way guarantees the debts of an individual, association, or private corporation.

  (4) Certain debts barred. The General Assembly shall never assume or pay any debt or obligation, express or implied, incurred in aid of insurrection or rebellion against the United States. Neither shall the General Assembly assume or pay any debt or bond incurred or issued by authority of the Convention of 1868, the special session of the General Assembly of 1868, or the General Assemblies of 1868-69 and 1869-70, unless the subject is submitted to the people of the State and is approved by a majority of all the qualified voters at a referendum held for that sole purpose.

  (5) Outstanding debt. Except as provided in subsection (4), nothing in this Section shall be construed to invalidate or impair the obligation of any bond, note, or other evidence of indebtedness outstanding or authorized for issue as of July 1, 1973.