WASHINGTON (AP) — Newly empowered congressional Republicans challenged President Barack Obama at both ends of the Capitol on Tuesday, voting in the House to repeal the health care program he signed into law but faltering in an initial Senate attempt to roll back immigration policies he issued on his own.

There was a third challenge as well, as Republican leaders announced the House would give final approval next week on legislation clearing the way for construction of the Keystone XL Pipeline. That would trigger Obama’s threatened veto, the first in a new era of divided government.

The skirmishes all seemed likely to end in eventual defeat for Republicans, but served as a potent reminder of their power after Obama challenged them bluntly last month with his State of the Union address and a no-balance budget on Monday calling for higher taxes and new spending. The GOP won control of the Senate in last fall’s elections, and has its largest House majority in nearly 70 years.

Badly beaten in last fall’s elections, Democrats were defiant.

“They’re baying at the moon, something that is not going to work,” said the party’s leader in the House, Rep. Nancy Pelosi, referring to Republicans as the health care vote neared.

The vote was 239-186 to repeal the health care law known as Obamacare. Similar votes have been held more than 50 times in the four years, but the day gave newcomers to Congress their first opportunity to vote to uproot the health care law they campaigned against last fall.

“Today, I am making good on my commitment to support a full repeal of Obamacare,” said Rep. Alex Mooney, a West Virginia Republican who took his seat in Congress last month.

The day’s vote was marked by a second difference. The bill included instructions to key committees to begin work on a replacement that the party promised in the 2010 political campaign. Officials described that as a measure of preparation in case the Supreme Court overturns a key portion of the existing program in a ruling expected this June.

Only three Republicans opposed repeal of the program, Reps. Bob Dold of Illinois and first-termers John Katko of New York and Bruce Poliquin of Maine.

Across the Capitol, Democrats blocked debate on legislation to fund the Department of Homeland Security and simultaneously overturn presidential executive orders that have spared an estimated four million immigrants in the country illegally from the threat of deportation. The vote was 51-48, nine shy of the 60 needed to begin work on the measure.

Senate Democratic Leader Harry Reid said his rank and file would continue to block action on the measure until Republicans agree to strip out the immigration provisions.

Echoed by other Democrats, he said Republicans were “playing politics with national security,” citing the execution-by-burning earlier in the day of a Jordanian pilot held hostage by Islamic terrorists in the Middle East as evidence of a threat.

Senate Majority Leader Mitch McConnell of Kentucky said that by issuing his immigration policy by executive order, Obama had committed a “power grab” that exceeded his authority as president.

“So I’m calling on Democrats to vote with us now to fund the Department of Homeland Security. I’m calling on Democrats to join us and stand up for core democratic principles like the rule of law and separation of powers,” he said.

It was an offer they refused, unanimously. A total of 51 Republicans voted to advance the bill, while all 44 Democrats, two independents and two Republicans were opposed. The two GOP opponents included Sen. Dean Heller of Nevada, whose state is home to a large Hispanic population, and McConnell, whose vote will permit him to call for a revote in the future.

The Department of Homeland Security will lose a portion of its funding on Feb. 27 unless Congress has acted by then.

Rhetoric aside, the vote appeared to be part of a delicate dance in which the Senate GOP leadership, knowing it lacked the votes to prevail, wanted to demonstrate as much to anti-immigration lawmakers who helped pass the measure through the House last month. The provisions that drew objections from Democrats would roll back administration policies that shield millions of immigrants from the threat of deportation even if they are in the country illegally, and also give protection to younger immigrants brought to the country unlawfully by their parents.

Speaker John Boehner, R-Ohio, said it was up to Republicans like Sen. Ted Cruz of Texas and Jeff Sessions of Alabama as well as Democrats to “stand with the American people and to block the president’s action.” The two Republicans were influential in the House’s decision to toughen the immigration provisions of the House bill, and officials said Boehner’s remark was a challenge to them to make sure the Senate follows suit.

The speaker did not say what the next step would be if, as expected, the bill was bottled up in the Senate. But Rep. John Carter, R-Texas., said the House may eventually have to pass a second bill that extends funding without immigration-related provisions attached. “Ultimately there may be a clean bill sent,” he said.

Republican senators were searching for another way out. Moderate Sen. Susan Collins, R-Maine, said late Tuesday she was working with Cruz and others on alternate legislation funding the Homeland Security Department and rolling back the new administration policies limiting deportations, but keeping in place protections for immigrants brought here as kids. But with Democratic leaders demanding a clean bill, it was not clear Collins’ proposal would shift the debate.

The announcement that Congress would soon send Obama legislation to approve construction of the Keystone XL pipeline meant the House would accept relatively minor changes that the Senate added when it passed the bill. Among them is a non-binding statement that climate change is not a hoax.

Democrats say they have enough votes to sustain a veto to the measure.

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Associated Press writers Erica Werner and Andy Taylor contributed to this report.