Presentism and Truthmakers

Bill runs through the truthmaker objection to presentism:  truths about the past are truths now and hence need present truthmakers yet under presentism there don't seem to be any.  Let's consider a variant of Bill's example: 

S. Kennedy commanded PT109.  

That's true.  But what in the present grounds this truth? On the face of it, that's a rather weird question.  Why should we expect there to be something about the world now that grounds a truth about the past? But Bill has a point I think: we say that S is true, now.  Bill rightly dismisses Ed Feser's half-hearted attempt to reconcile presentism and truthmakerism.  So what should we say about this puzzle?

Consider this sentence:

T.  Kennedy commands PT109.

In 1943 T was true and we may suppose that in 1943 the world was in some way that made it true.  But now in 2019 that way has long since ceased to be and T is no longer true.  How then do we express the way of 1943 from the vantage point of 2019?  We can't just use T as that is false.  Instead, the rules of English, unchanging over the intervening period, tell us to use S, a modification in tense of T.  The past way, once expressed by T is now expressed by S.  S is not a brute truth.  It's a rule-governed transformation of a made truth.