Possible Clues:

• Pictorial pastiche artist erased, to be artful
• Keeping it in force not entirely advisable
• Prudent guard not entirely guarding it
• Prudent; discreet
• Wise polemicists ignoring mess
• It could be expedient if most of 21 down steal one time
• Sagacious, well-mannered for the most part and in charge
• Statesman-like, still keeping Oscar fired up
• Prudent, sagacious
• Prudent Garda ignores second last number ringing it back