Consider a startup with a small number of founders (lets imagine 2 to 4). At some point down the line a difference of opinion developed (such as market to target, or if to continue or fold) that can't be resolved in the normal way.
What can you do to ensure that organisational paralysis doesn't ensue?
Make a point to document and get into legal contracts if necessary as much as possible up front. There should be provisions to reevaluate everything in the future.
Get it all in the open.
Personally, I would solve this using a business plan. I've been in situations where of the 2-4 founders, each of us had a unique skill set, and by setting up a business plan, we could focus the business goals and at a hight level, keep ourselves on the same page. A decent business plan with future planning (1, 6, 12, 24 and 60 month planning, more abstract the farther you go in time) that is a living document, combined with each of us working toward those goals in our section of the business, does amazing things.
To strengthen that, you could also add radical change clauses, as well as majority consent to any major directional changes. This means the business should be able to function for an extended period of time, while all founders work together to come to an agreement, if change occurs.
I think at the end of the day, people changing (or changing their minds) is just part of going into business with someone. If you have concerns about this, most of the time you can structure your business to handle it at the beginning, while you are all still agreeing on things. This can be rough if you're the one wanting change, but it protects the idea that caused you to form an entrepreneurial partnership. It's also another in a long list of reasons to make sure you're careful who you found companies with, and who you bring in as employees/contractors.
Hope that helps.
The best way to start a relationship between co-founders is to have a shareholders agreement which decides the basic framework within which the founders will operate. The agreement can also state up front the decisions which will a unanimous vote of all founders, which will ensure that decisions are taken in the interest of of all parties. A business plan can be made a schedule to the shareholders agreement to ensure that it is adhered to. Otherwise you may find that business plans are easiest to digress.
There are a number of devices that exist to solve these sorts of problems. You need to talk to a lawyer practicing in this area in the jurisdiction where you are incorporating.
Options include requiring all votes to be unanimous (forces you all to get along from the start), favourable buy-out/drag-along/tag-along/russian roulette terms (allowing disaffected parties to cash out, and creating a financial problem for the business if a split happens), some kind of casting vote structure (e.g. chairman has the casting vote, and chairmanship rotates, or allocate casting vote by lot), or a coin-toss provision.