The word in what you have quoted (though you didn't give the source) was doubtless moderates--plural. It is not an adjective here; it's a noun.
Pelosi, who has been the Majority Leader in the US House of Representatives and will be the Minority Leader in the new year when her party, the Democrats, will be in the minority, is viewed as a strong and outspoken advocate of her party's policies. Moderates (of any party) refers to those who are seen as less adamant about staying with their positions and more willing to compromise. The writer of the text you quote believes that this situation may lead to public disagreements within the party.