Taking Constantinople was not easy. The Nicaeans and the Bulgarians launched a joint attack in 1235, and got nowhere. As long as the Venetians held the sea lanes open, and barring an event like 1261, the city will hold. All the more so since Theodore's rear was not secure, with Bulgaria as a constant threat. The quick collapse of his "empire" after 1230 also shows that he should spend more time on consolidating it. What Theodore certainly can do (and almost did) is reduce the Latin Empire to a city-state doomed to fall. In addition he could go on to recapture the Latin states of southern Greece, although here he is bound to face some stiff opposition at this time.