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“I can truly be a unifying figure, then I will gladly serve,” he said Tuesday night to reporters after a House GOP conference meeting.
On Tuesday, Ryan laid out his vision for the conference and the terms of his service -- including changes to House rules, time for his family and a forward-looking GOP agenda.
“We need to move from an opposition party to being a proposition party,” he said.
Chief among his demands is a mandate: Ryan, who already has the support of most Republicans, wants endorsements from every corner of the conference by Friday -- including the House Freedom Caucus who helped force Boehner out and led Kevin McCarthy to abandon his speaker bid.
He met with leaders of that group late Tuesday afternoon, but did not emerge with any commitments.
Ryan has repeatedly turned down opportunities to lead House Republicans in the past, and said for weeks after Boehner's announcement he would not run for speaker.
On Tuesday, the father of three school-age children still sounded uneasy about his proposed commitment.
“I consider to do this with reluctance,” he said. “I genuinely worry about the consequences my agreeing to serve will have on [my children].”
But Ryan, who has spent most of his professional life on Capitol Hill, said it came down to his sense of duty.
“My greatest worry is the consequence of not stepping up, of someday having my own kids ask me, when the stakes were so high, why didn't you do all you could do?” he said. “I came to the conclusion that this was a dire moment.”
Republicans leaving the conference meeting Tuesday night said Ryan's announcement was met with enthusiasm and applause.
"He understands how to bring us together," said Rep. Barbara Comstock, R-Virginia.
Several speaker candidates, including Reps. Jason Chaffetz, R-Utah, and Ryan Zinke, R-Montana, said they would abandon their own speaker bids and support Ryan.