WASHINGTON  John Boehner, who rode the Republican landslide in last year's congressional elections to the House speaker's chair, took the gavel Wednesday promising "transparency, greater accountability and a renewed focus on the Constitution."

In a speech noting his Catholic roots, the 61-year-old son of working-class Cincinnati neighborhoods spoke of humility, openness and responsibility. He also acknowledged "great challenges" — unemployment and rising debt among them.

He also promised the minority Democrats they would be heard. But no sooner had he stepped down from the speaker's chair than a party-line fight erupted over GOP rule changes.

"Actually, my head is somewhat spinning," said Rep. Louise Slaughter, D-N.Y., addressing the speaker pro tem after Boehner left the speaker's chair to become master of ceremonies for a series of opening day events. "Because not 20 minutes ago, the new speaker of the House of Representatives stood where you are and said he was going to be listening to people."

Democrats objected to a new rule stripping territorial delegates of their voting power and to changes in "pay-as-you-go" budgeting that will allow for tax cuts without any corresponding spending cuts to prevent the deficit from growing.

Congressional watchers said Boehner's promises of open governing would clash with an ambitious agenda that includes repealing last year's health reform law, cutting spending, targeting Obama administration regulations and streamlining the tax code.

All are must-pass measures for many of the newly elected Tea Party-backed Republican members who helped elect Boehner speaker.

"We're very soon moving from low-key discussions of openness and bipartisanship and humility into pedal-to-the-metal confrontation," said Norm Ornstein of the non-partisan American Enterprise Institute. Boehner's address "was a lovely, reasonable, statesmanlike speech, with a commendable and appropriate level of humility. But it masked the bubbling cauldron that the House is going to become any moment."

Across the Capitol, the Senate paused to honor Sen. Barbara Mikulski, D-Md., who becomes the longest-serving female senator in history.

With a 53-member Democratic majority, the Senate then took up the question of the filibuster, debating a change in the rule that governs the ending of debates.