The lines seem to be drawn with Barbour relying on Section 73 of the MS Constitution and Hood relying on the the decision in Barbour v. Delta Correctional Facility Authority, 871 So.2d 703 in which the MS Supreme Court ruled a line-item veto as unconstitutional. My reading of this opinion is it was narrowly tailored to address what appears to be a rather unusual situation with correctional appropriations. I found the dissent by (soon to be departing the Court) Justice Cobb more persuasive and helpful to show that there is also case law supporting the ability to use a line-item veto in certain circumstances. What these cases seem to turn on is whether the bill is an appropriations bill (see Sec. 69) or not. Theoretically all appropriations are supposed to be done only in appropriations bills but bleedover is not that uncommon where legislating is combined with funding. If it is an appropriation then the governor can line-item veto, if not then no line-item option. The bills in question here are HB 1681 and HB 1689 both of which appear to be appropriations bill to me and therefore able to be line-item vetoed.
Section 73. Veto of parts of appropriations bills.
The Governor may veto parts of any appropriation bill, and approve parts of the same, and the portions approved shall be law.
Section 72. Approval or disapproval of bill by Governor; veto override process.
Every Bill which shall pass both Houses shall be presented to the Governor of the state. If he approve, he shall sign it; but if he does not approve, he shall return it, with his objections, to the House in which it originated, which shall enter the objections at large upon its Journal, and proceed to reconsider it. If after such reconsideration two-thirds (2/3) of that House shall agree to pass the Bill, it shall be sent, with the objections, to the other House, by which, likewise, it shall be reconsidered; and if approved by two-thirds (2/3) of that House, it shall become a law; but in all such cases the votes of both Houses shall be determined by yeas and nays, and the names of the persons voting for and against the Bill shall be entered on the Journal of each House respectively. If any Bill shall not be returned by the Governor within five (5) days (Sundays excepted) after it has been presented to him, it shall become a law in like manner as if he had signed it, unless the Legislature, by adjournment, prevented its return, in which case such Bill shall be a law unless the Governor shall; veto it within fifteen (15) days (Sundays excepted) after it is presented to him, and such Bill shall be returned to the Legislature, with his objections, within three (3) days after the beginning of the next session of the Legislature.
Section 69. Contents of appropriations bills.
General appropriation bills shall contain only the appropriations to defray the ordinary expenses of the executive, legislative, and judicial departments of the government; to pay interest on state bonds, and to support the common schools. All other appropriations shall be made by separate bills, each embracing but one subject. Legislation shall not be engrafted on the appropriation bills, but the same may prescribe the conditions on which the money may be drawn, and for what purposes paid.
link to the blog of the cartoonist who did the below cartoon.