The most common and most likely answer to this crossword clue is the 5 letter word RULES
I've seen this crossword clue in The Daily Telegraph
R
U
L
E
S
More clues leading to the result RULES
- Regrets accepting Liberal regulations
- Regrets adopting liberal laws
- Slight setback hampering European policies
- Decides code
- Decides officially and draws the line
- Australian football is supreme, OK?
- The French following Rugby Union laws
- Regrets holding Liberal principles
- Draws the line at regulations
- The French will support game's regulations
Buddy explains!

The straight part
We know that "Draws the line at/regulations" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case draws the line at/regulations = rules.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does RULES mean?
RULES noun- A regulation, law, guideline.
- A ruler; device for measuring, a straightedge, a measure.
- A straight line (continuous mark, as made by a pen or the like), especially one lying across a paper as a guide for writing.
- A regulating principle.
- The act of ruling; administration of law; government; empire; authority; control.
- A normal condition or state of affairs.
- Conduct; behaviour.
- An order regulating the practice of the courts, or an order made between parties to an action or a suit.
- A determinate method prescribed for performing any operation and producing a certain result.
- A thin plate of brass or other metal, of the same height as the type, and used for printing lines, as between columns on the same page, or in tabular work.
- To regulate, be in charge of, make decisions for, reign over.
- To excel.
- To mark (paper or the like) with rules (lines).
- To decide judicially.
- To establish or settle by, or as by, a rule; to fix by universal or general consent, or by common practice.
- To revel.