This article in In These Times by 8 veterans of the democratic socialist left has a timely warning for the DSA about the dangers posed to DSA by the entry of democratic centralist organizations:
"As DSA has grown in size and political influence, so too has the interest it has attracted from small political groups to its left. These “sects,” short for sectarian organizations, see opportunities for themselves in the large numbers of young people new to politics who have joined DSA, viewing them as potential recruits for their emaciated ranks.
The recent announcement of the Trotskyist organization Socialist Alternative (SAlt) that its members were coming aboard, followed by a similar declaration from its leading member, Kshama Sawant, has simply made public a process that has been underway for some time — that various marginal Trotskyist organizations have infiltrated the DSA in a practice known as “entryism.”
The authors go on to provide a useful overview of entryist tactics on the US left and the generally baleful effect such tactics have had on the health of mass progressive organizations like the Socialist Party and SDS. In my view, the DSA has already moved far enough to the left (note the slogan on the DSA activist's shirt in the photo) that they've probably set a fairly low ceiling on how large and influential the organization can get. More Trotskyist and other democratic centralist entryism would simply ensure that course corrections to raise that ceiling would become impossible and even raise the specter of precipitous organizational decline.
Those who fail to learn from history are doomed to repeat it.