Wedding venue

Anyone can sue anyone, the question is if they have a good claim.  Here, depending on what exactly your contract provides,  it appears that the venue does have a good claim.  With the exception of some statutory rights to cancel some kinds of contracts before a short period of time has expired (usually 3 days), or if the contract itself allows for cancellation under certain contingencies, you don't have a right to cancel a contract.  You are obligated to perform your contracts, and if you don't you are liable for the damages that your breach causes the other party.  For example, some contracts to buy real property have a mortgage contingency clause which allows you to cancel the contract if you're not approved for a mortgage, but absent such a clause you are liable to buy the house, mortgage or not.  If you move out of an apartment 3 months before the lease is up, you're still responsible to pay the last 3 months rent.  If the venue is able to book another event for the time yours was scheduled, the amount  you owe may be reduced by the amount the venue receives, and if it gets as much from the new booker as it would have from you, you may not have to pay any damages, but if not you could be liable for the full amount of your contract, minus any expenses the venue saves by the cancellation.  You should probably consult a Missouri attorney.