[Albert Moulton]

With a straddle on the table, you should raise more to avoid giving the straddler excellent odds to call preflop with speculative hands, especially if you are raising from one of the blinds.

So, if you usually open raise 3-5xbb, then with a straddle, you should probably open raise 6-8xbb when in position vs the straddler, and maybe 10 or more x bb (depending on how many others limped) when raising from the blinds.

In short, the answer is that your raise size should be bigger. Basically, the game is playing with effective stacks that are half of their usual size for that round and you should treat your preflop and post-flop play accordingly. In a 100bb effective stack game, the hand with a straddle becomes a "50bb" effective stack game. In general, big pairs go up in value, and implied odds associated with hands like suited connectors go down in value. Implied odds to flop a low-to-medium sized set in a raised pot also go way down.

In some cases, if you are the BB, you might try to make a big raise to steal the limper's dead money before the straddler has a chance to do it. You should occasionally try that with the worst of the hands you might otherwise call with (like K9s), as well as with all your very good hands (like AQs+/JJ-AA).

In very rare cases, you will want to deep limp in a straddled pot with aces if you have a straddler who habitually raises and/or pushes with a very wide range of preflop hands (any pair, Ax, any broadway, etc.).