Interesting. I had the same thought. I always thought the correct word was "toe", but recently thought that one place you toe the line was in a tug of war, where you start by toeing the line but end up towing the line.
But the one that really bugs me is "reign in" or "free reign".

I may be completely off base. I had thought it came from the old bare-knuckle boxing matches. Fighters had to come up to a mark (toe the line) to prove they were still in the fight. Failure meant they were too beaten or fatigued.

It is indeed "toe the line" with the explanation given over at Watts Up With That: You had to not just line up, but line up very precisely with your toes exactly on a line. Hence the implication of absolute obedience.

"Toe the line" is the origin of the phrase. Popular etymology has transformed it to "tow the line." I get an image of the Volga boatman from that corruption; I suspect a transference from the lyrics in "Old Man River:" "tow that barge, lift that bale."

It definitely comes from military jargon for inspections in rank. You had to line up with the toes of your shoes on an imaginary line with the rest of the rank (row). It means you'd better get even the smallest details right because we're checking. An alternative phrase is "toe the mark". Another common phrase to come from this is "pass muster" or "that won't pass muster". Muster is another word for morning assembly of troops for inspection (the ranking NCO would muster the troops for inspection). If there were deficiencies in your weapons cleanliness, personal grooming or uniform, you wouldn't pass muster. Today the phrase has been corrupted to "that doesn't cut the mustard".
Whatever.

No matter how one cuts the mustard, the two phrases don't mean the same thing. What Simon describes as the meaning for "tow the line" is better expressed by "carry water". "Tow the line" really doesn't have much in common with "carry water".

"Cut the mustard" does not mean the same thing as "passing muster" either, and it's not likely derived from that phrase.

When I read posts or comments that confuse these phrases, I question the precision of thought given. This is entirely different from the common online typos (its - it's, who's - whose, their - there - they're).

Those are mostly a matter of muscle memory overtaking intention. Annoying, but not usually pertinent to meaning. There is validity to the argument that misusing the other phrases is the same. Perhaps, sometimes.

Other misused phrases that make me question the thought behind the writing are:

make due for make do;

intensive purposes for intents and purposes;

reign for rein (mentioned above, and might fall into the typo category);

mute point for moot point;

peaks interest for piques interest;

And on and on. The bottom line is that clear thinking and clarity in communication require knowing the meaning of the words and phrases used.

And... yep, this touched on one of my pet peeves :-)

can anyone explain, "Draggin' the line?"

Two schools of thought on this one, historically.

The first places the root use of the phrase in pre-revolutionary Kingstown, where the would-be subversives became adept at disguising their homemade explosive devices as common foodstuffs. One day, the police had surrounded one small cell's home base, from which periodic small-arms fire and thrown cutlery were issuing in a rather hopeless attempt to keep out the hated government forces. The cell's small cache of grenade-like devices had been made to resemble common fruits, and then placed innocently throughout the hut, but the bomb-makers had neglected to inform anyone else in the group of this fact. As the police approached, one of the bomb-makers saw a fellow cell member crouched next to a window watching the advance, with a large bowl of fruit on the table upon which he leaned. Not realizing that the watcher didn't know that some of the fruit was actually weaponry, the bomb-maker began yelling to him "Tro da lime, tro da lime . . .!!" The watcher snapped his head back to see who was calling to him, and then, as might be expected, tossed one of the limes to him. Once the wreckage was cleared and the movement disbanded, the now-mangled phrase became a derisive reminder that, no matter what our intentions might be, ignorance usually causes us to act in furtherance of established authority.

The second line of thought holds, as does Charlie above, that the phrase arose in early English fighting matches, in which the fighters had to signal their ability to continue at the start of each round by approaching, and then standing at, a specific spot upon command. It was the willingness and ability to follow that specific command that translated into the meaning of the phrase as we understand it today.

Anyone who thinks the proper expression is 'tow the line' has another think coming.

Thomas,

It all depends on what you are trying to express.

If you want to be, I dunno, "correct", rather than "making stuff up", use "toe the line" or "toe the mark". The dictionary here says the phrase means "to adhere to doctrines or rules conscientiously; conform."

"Popular etymology" also substitutes "would of" for "would've" (i.e. "would have"). A popular misspelling based on pronunciation is not a good excuse for incorrect usage. Kinda makes you look dumb, I have to say. Or do I have another thing coming?

Hazy,

English has no fixed rules. New phrases are coined all the time. Just because they sound similar to other phrases does not discredit them.

The French have language police. English has no such organization to keep the language pure.

I like "tow the line" for some uses because of its punning nature. YMMV.

One may tow a barge with the assistance of a line, but one can never tow a line.

Toe the line it is.

Bill,

Have you never heard of mixing metaphors?

I kind of like it because of the pun nature of the phrase.

Besides there is a long history in English of words and phrases that are "incorrect" becoming a part of the language.

It amuses me.

And if you want to have even more fun you could say that "tow the line" is a synonym for "carry water".