In Julius Caesar, does Shakespeare portray Calpurnia and Portia as women of power and strength?

Calpurnia and Portia, though they have considerable strength of mind, do not seem to possess much power. Both are dependent on their husbands and can only plead with them. Calpurnia wants her husband to stay home because she is (rightly) terrified by her bad dreams and all the strange happenings that have been reported.

Caesar, I never stood on ceremonies,
Yet now they fright me. There is one within,
Besides the things that we have heard and seen,
Recounts most horrid sights seen by the watch.
A lioness hath whelped in the streets;
And graves have yawn'd, and yielded up their dead;
Fierce fiery warriors fight upon the clouds,
In ranks and squadrons and right form of war,
Which drizzled blood upon the Capitol;
The noise of battle hurtled in the air,
Horses did neigh and dying men did groan,
And ghosts did shriek and squeal about the streets.
O Caesar! These things are beyond all use,
And I do fear them.

Calpurnia's husband ignores her completely and goes to meet his doom at the Capitol. So while Calpurnia may be strong in the sense that she has correctly read the signs of unrest in the city, she lacks power in a patriarchal society.

Portia too has to plead with her husband, Brutus, to get what she wants. She manages to persuade her husband to confide in her, but this modicum of power is achieved only with great effort:

You have some sick offense within your mind,
Which by the right and virtue of my place
I ought to know of; and, upon my knees,
I charm you, by my once commended beauty,
By all your vows of love and that great vow
Which did incorporate and make us one,
That you unfold to me, yourself, your half,
Why you are heavy, and what men tonight
Have had resort to you; for here have been
Some six or seven, who did hide their faces
Even from darkness.

Like Calpurnia, Portia is deeply concerned in Act 2, Scene 4 after she learns the answers to all her questions. Portia may have succeeded in learning about the conspiracy, but she is unable to interfere in it. So while Portia has the wisdom to regard events with trepidation, she, like Calpurnia, is unable to change the situation.

Calpurnia and Portia appeal to their husbands with their feelings, their insights, and their devotion. Both Caesar and Brutus are on fatal courses, but they do not realize that their wives are closer to the truth. Caesar, of course, should have listened to Calpurnia. We know she is speaking truthfully and with love, while he is surrounded by smiling men who have swords and daggers concealed beneath their robes. Portia knows that her husband has gotten himself involved in a perilous plot with a group of inferior and self-serving men. Her wisdom tells her that the assassination attempt may be successful but that will not be the end of it. She herself will commit suicide in a horrible manner by swallowing burning coals pulled out of the fire. Both these women are rightfully distressed by the arrival of the Ides of March. Their own fates are bound up with those of their husbands—but unlike their husbands, they don't have the power to effect change.