MY DEAR SIR: Thanks for your kind letter just received. I was not aware of a disposition in the West to resist the act of the President in regard to Gen. Frémont; though I was aware that there was very great dissatisfaction in that part of the country at the want of enterprise and energy on that part of our Grand Army of the Potomac. We are fighting to sustain constitutional government and regulated liberty, and, of course, to set up any military leader in opposition to the constituted authorities would be utterly destructive of the very purpose for which the people of the loyal states are now so liberally contributing their blood and treasure, and could only be justified in case those charged with the administration of affairs were betraying their trusts or had shown themselves utterly incompetent and unable to maintain the Government. In my opinion this rebellion ought to and might have been crushed before this. I have entire confidence in the integrity and patriotism of the President. He means well and in ordinary times would have made one of the best of Presidents, but he lacks confidence in himself and the _will_ necessary in this great emergency, and he is most miserably surrounded. Now that Gen. Scott has retired, I hope for more activity and should confidently expect it did I not know that there is still remaining an influence almost if not quite controlling, which I fear is looking more to some grand diplomatic move for the settlement of our troubles than to the strengthening of our arms. It is only by making this war terrible to traitors that our difficulties can be permanently settled. War means desolation, and they who have brought it on must be made to feel all its horrors, and our armies must go forth using all the means which God and nature have put in their hands to put down this wicked rebellion. This in the end will be done, and if our armies are vigorously and actively led will soon give us peace. I trust that Gen. McClellan will now drive the enemy from the vicinity of the Capital--that he has the means to do it, I have no doubt. If the case were reversed and the South had our means and our arms and men, and we theirs, they would before this have driven us to the St. Lawrence. If our army should go into winter quarters with the Capital besieged, I very much fear the result would be a recognition of the Confederates by foreign Governments, the demoralization of our own people, and of course an inability to raise either men or money another season. Such must not be. Action, action is what we want and must have. God grant that McClellan may prove equal to the emergency. Yours very truly, LYMAN TRUMBULL.