Given a sentence and two mentions from the text (arguments), indicate a phrase (a verb or noun phrase) that describes the relationship between the provided arguments.
Q: Sentence: 'I was speaking with former Massachusetts Gov. Mitt Romney about Sen. John McCain 's new line of attack against Sen. Barack Obama .', Argument/Subject 1: 'obama', Argument/Subject 2: 'mccain'
A: 
be attack