When people spar[verb] (or have a spar[noun]) over some topic, they have a friendly argument.

Phelps invited Ted Frederickson, associate professor of journalism, to a spar on the issue of "homosexuals and the military".

 

Phelps invited Ted Frederickson, associate professor of journalism, to spar over the issue of "homosexuals and the military".

ODO:

spar
NOUN

1 A period or bout of sparring.

‘Remembering the spars she had had with the brothers, she smiled.’

VERB

[NO OBJECT]
1.1 Argue with someone without marked hostility:
‘mother and daughter spar regularly over drink, drugs, and career’

When people spar[verb] (or have a spar[noun]) over some topic, they have a friendly argument.

Phelps invited Ted Frederickson, associate professor of journalism, to a spar on the issue of "homosexuals and the military".

Phelps invited Ted Frederickson, associate professor of journalism, to spar over the issue of "homosexuals and the military".

ODO:

spar
NOUN

1 A period or bout of sparring.

‘Remembering the spars she had had with the brothers, she smiled.’

VERB

[NO OBJECT]
1.1 Argue with someone without marked hostility:
‘mother and daughter spar regularly over drink, drugs, and career’