In his first coordinated offensive, Scott gave leave to McDowell to move south in terms of orders, objectives, timing etc., just as he did Patterson in the second offensive.
The correct orders to McDowell and Patterson in their supporting roles should not have been to make a demonstration or attack (on their own terms, opportunity permitting) but rather for the supporter to interpose his forces between Beauregard and Johnston. This would have put Patterson on ground east of Johnston and McDowell west of Beauregard in the two early war offensives.
Geography and history make hash of this ideal because the Manassas Gap railroad ran behind the two Confederate positions. The road to mutual reinforcement ran due south, then east or west, not due east or west from the respective defensive positions. To practically interpose between the positions, the Union army would need to go way way south first, a logistic and tactical impossibility, given the starting positions.
This is a way of saving that the correct, textbook solution was not available to McDowell or Patterson's armies. Interposition due east or west of the enemy, which was within their means, had no effect on rail use for reinforcement.
Now, follow this. Unless I am in error (Harry can correct me), Johnston's use of the railroad was a surprise. Proof: in an exchange with Patterson (in the OR), Scott gives him the condition during McDowell's offensive, that should Johnston move towards Beauregard, Patterson is to follow along the Virginia side of the Potomac, using the canal to supply his forces.
This is not a contingency that envisions Johnston moving along the way southerly Manassas Gap railroad by steam or sinew, is it? It seems to suggest Scott envisioned Rebel forces joining by northerly roads such that following the river would be following Johnston's army en route to Beauregard's positions. Scott envisions Johnston moving more or less due east of his defenses.
So, Scott's orders in the two offensives to the "distractors" are in both cases theoretically wrong even though, had right orders been issued, it would not have availed him due to the railroad's location. The orders were wrong in terms not just of the ideal but in terms of the land movement options Scott envisioned for the Confederates.
Johnston's assumption of the defense in Winchester put him in marching distance of a railroad connection. It was a far enough away march that it obscured the potential connection to Union analysis. It was southerly enough that interposition by Patterson was impossible, had Johnston's railway ride been suspected or envisioned.
Hattaway and Jones took some trouble to explain why Civil War armies could not be destroyed, or even seriously hurt during a retreat after battle. Johnston was not retreating after battle; he was evacuating a position. To stop an evacuation through offensive action seems both theoretically and practically impossible in a Civil War context.
This makes nonsense of the contemporary criticism of Patterson that he "could have" [fill in the missing accomplishment of your choice]. He had the wrong orders from Scott based on a false concept of the enemy's options and potential - no basis for a plan or a result. Contemporary people were down on Patterson because they did not know you can't fix an enemy army in place that is evacuating (not with ACW means and methods); and these critics willfully disregard that Johnston's rail movement occurred far beyond the reach of Union forces. (Look at the map at the distance of Winchester to the railroad and picture the options for a wagon-bound enemy.)
It seems sad that so many modern historians have never moved beyond the limited, in fact asinine, opinions of that day and moment but here we are. Welcome to Civil War history!
There is an indubitable point to be made that Patterson set himself some goals or objectives and failed to meet them (and later characterized them as mere contingencies, not ends). As was said of a friend of mine in a performance review, "He failed to meet even the low standards he sets for himself." I think Patterson might have met some of those modest goals he set for himself, if not for two pre-emptive blunders he committed in mid-campaign.
These are nearly inconceivable in scale, yet never mentioned as errors in Civil War histories or held against Patterson; both tie into Scott's failure in the second offensive end game, at which point we'll conclude this thread.