Ablative of Agent

In translating the following, I have stumbled upon confusion :

Perīculum rēgnō magnum fīliīs līberōrum vidētur.

I would like to say it means :

A great danger to the kingdom is seen by the sons of the free.

OR

There seems to be a great danger to the kingdom to (in the opinion of) the sons of the free.

BUT

I guess interpreting it that way would require “sons of the free” to be an ablative of agent, which I understand should be preceded by ā or ab. That is missing here.

Any help, anyone?

How about the dative.

Allen and Greenough 375 B

b. The dative of the person who sees or thinks is regularly used after videor, seem: -

  • vidétur mihi it seems (or seems good) to me.

    \
  • dís aliter vísum [est] (Aen. ii. 428), it seemed otherwise to the gods.

    \
  • videor mihi perspicere ipsíus animum (Fam. iv. 13. 5), I seem (to myself) to see the soul of the man himself.

Mille gratias, Paule… Question: Is this use with “videor, videri, visus sum” EXCLUSIVE, or one could still have used the ablative of agent “a filiis” to express the same idea?

Offhand, I cannot think of videor being used with Ablative. I also cannot think of a passive “think” that uses ablative of agent.

If you were to use the ablative of agent (ab/a + ablative w/passive verb] the meaning would be quite literally “the danger is seen by the sons of the free,” i.e. it is perceived definitely by them, rather than merely appearing to be so to them. There is no separate verb equivalent to “seem” in Latin, so the passive of video functions in that capacity instead whenever it is used with the dative.