insist upon (?.)

• advocate
• always trot out
• assert
• attach a condition
• belabor
• blandish
• brook no denial
• cajole
• call on
• call upon
• coax
• compel
• condition
• constrain
• contend
• dictate
• dwell on
• dwell upon
• exhort
• hammer away at
• harp on
• have a catch
• have a joker
• high-pressure
• importune
• insist
• insist on
• jawbone
• labor
• lobby
• maintain
• make conditional
• make contingent
• nag
• necessitate
• oblige
• persist
• plead with
• press
• pressure
• push
• recommend
• soft-soap
• stand on
• stick to
• stipulate
• sweet-talk
• take no denial
• thresh over
• urge
• wheedle
• work on