- State filibusters are rare: This article provides a good overview, noting that only Alabama, Nebraska, South Carolina and Texas see filibusters with any regularity. Vermont is a surprising entry on the list of states where a filibuster is possible, but apparently some combination of the State culture, the part-time nature of the job, and the types of people elected to the VT state senate means that in practice the minority doesn't filibuster things it opposes.
- Delaware: Delaware's Senate is weird and secretive. Their rules are evidently not posted online. From perusing Delaware Liberal, it seems like DE Senate is majority rule, but absent some direct evidence I opted not to include it.
- Maine: Maine's Senate rules are really not very explicit. It's not clear to me how the ME Senate ever moves from debate to a vote, but as there is no provision for limiting debate or invoking the "previous question" (meaning roughly in legislatese "let's stop talking about X and just vote on X"), then I presume it requires unanimous consent and could be filibustered.
- Other minority obstuction tricks? I did try to watch for states where more than a majority was needed for quorum, but didn't notice any aside from Texas. The "disappearing quorum" is a classic mechanism of minority obstruction where the minority simply just doesn't show up, and the rules require at least some of them to be there for the chamber to conduct business. DQ is more extreme than the filibuster since it can entail fleeing the Sergeant-At-Arms who is usually (possibly always) empowered to compel the attendance of legislators. There is also tricks like unending amendments, however in most cases the States with "previous question" rules have them written such that once invoked (and the motion for the previous question itself is always non-debatable that I saw), further amendments are also out-of-order. That said, if you spot a state on my list of non-filibuster states that has some other parliamentary trick for prolonging the process indefinitely, point it out.
- State Houses/Assemblies: I didn't investigate the rules of State lower chambers very much. Generally if there is going to be a minority obstruction mechanism, it will be in the Senate. Texas has minority obstruction techniques in its House, and Vermont requires a 2/3 quorum when voting on tax increases, but again, if there are other states where the Senate is majority rule, but the House has the potential for requiring Supermajority rule, I'd be happy to know about them.
What about California? TABOR and other State constitutional supermajority legislative requirements?
I haven't ignored them. The NCLS provides this list of State budget vote requirements (only 3 need legislative supermajorities for the budget), and this list of state supermajority requirements to raise taxes. Notably absent from the second list is Colorado, the birthplace of TABOR, which in my estimation drops CO to "mixed" due to items like this. Between these three things, if you want to compile a list of states that can be governed on simple bi-cameral majorities, the 36 from above shrinks to 22 by my count:
| Majority Rule || Mixed || Supermajority |
| Georgia || Colorado || Alabama |
| Illinois || Delaware || Alaska |
| Indiana || Florida || Arizona |
| Iowa || Hawaii || Arkansas |
| Kansas || Kentucky || California |
| Massachusetts || Michigan || Connecticut |
| Minnesota || Mississippi || Idaho |
| Montana || Oregon || Louisiana |
| New Hampshire || || Maine |
| New Jersey || || Maryland |
| New Mexico || || Missouri |
| New York || || Nebraska |
| North Carolina || || Nevada |
| North Dakota || || Oklahoma |
| Ohio || || Rhode Island |
| Pennsylvania || || South Carolina |
| Tennessee || || South Dakota |
| Virginia || || Texas |
| Washington || || Utah |
| West Virginia || || Vermont |
| Wisconsin || || |
| Wyoming || || |
In this piece I tried to outline my taxonomy of "supermajority", "mixed" and "majority" but here I can simplify it to: Supermajority states are as bad or worse than the US Senate, mixed are better than the US Senate but still require supermajorities for some items like tax increases and majority rule are just as described.
By either metric however, we still only have less than half the US States operating on supermajority/anti-tyranny rules comparable to the US Senate's. My broad aim here was to show that the claims about the requirement for protection from majority-tyranny rule are belied by the frequent lack of such rules at the State level, and the evident lack of governing failures or absurdity ensuing from these. Rather than just assert it, I will provide some evidence. Looking at State level Gross-State-Product per-capita figures (2004 data), this table compares State GSP-per-capita against my categorizations of their democratic rules, by simple mean (not adjusted for population):
| Category || Simple Avg GSP Per Capita || Avg Rank |
| 50 States || $38,235.50 || 25.50 |
| Filibuster States || $36,701.78 || 30.15 |
| Non-FB States || $38,056.73 || 24.50 |
| Non-FB + Delaware || $38,974.38 || 23.86 |
| Majority Rule || $39,225.43 || 21.95 |
| Mixed Rule || $38,844.85 || 27.37 |
| Supermajority Rule || $36,902.85 || 28.65 |
| Supermajority with filibuster || $36,762.64 || 30.64 |
Delaware turns out to have by far the largest per-capita GSP, at $64K, and since its status as noted above was in doubt, I provde the non-filibuster states both with and without Delaware. To help correct that, I include the average of the States rankings from 1 to 50 in decreasing order of per-capita GSP, with 25.5 the mid-point. This helps smooth the effects of a few states like Delaware and Alaska which have significantly higher GSP figures.
From the data above we see that there is a pretty good unscientific relationship between filibuster status, and the ability of the majority to govern. Non-Filibuster states (with and without Delaware) beat filibuster states in both $ and average rank. Majority rule states get the highest GSP per cap, and highest average rank. Mixed come next (largely due to Delaware being treated as mixed in this analysis) and Supermajority states do worst. Even worse than supermajority states as a class are the subclass of supermajority states that also have a State Senate filibuster, with an average rank of 30.64 and a per-capita GSP. None of this rises to the level of statistical significance, as the standard deviation for the GSP is $7152 and for the rankings 14.57. However, given how well the results line up in order, I think there is some kind of relationship, even if below a 95% confidence level.
Mainly though, I am satisfied with the result that suggests that not having supermajority requirements of whatever sort does not lead to some kind of governing disaster. If I cannot prove that majority rule is postively correlated with wealthier states, then filibuster supporters cannot claim that majority rule is correlated with bad government or failing societies.
Certainly GSP is not the only metric of state success, but I think this puts the ball further into the court of those who wish to claim the filibuster is a necessary minority protection mechanism at the federal level. The onus should be on them to provide evidence for the harms that result from majority rule. What exactly are you afraid of? Rising per-capita incomes?