You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Party_leaders_of_the_United_States_House_of_Representatives

Context:
A party's floor leader, in conjunction with other party leaders, plays an influential role in the formulation of party policy and programs. He is instrumental in guiding legislation favored by his party through the House, or in resisting those programs of the other party that are considered undesirable by his own party. He is instrumental in devising and implementing his party's strategy on the floor with respect to promoting or opposing legislation. He is kept constantly informed as to the status of legislative business and as to the sentiment of his party respecting particular legislation under consideration. Such information is derived in part from the floor leader's contacts with his party's members serving on House committees, and with the members of the party's whip organization.

Question:
In what role are the floor leader's instrumental for legislation?

guiding legislation favored by his party through the House, or in resisting those programs of the other party that are considered undesirable by his own party