WASHINGTON >> House Speaker Paul Ryan today declined to say the evolving Republican tax cut plan won’t add to the nation’s already mammoth budget deficits. A chief goal of the effort will be to spark economic growth, he said.

Ryan (R-Wis.) said the GOP’s goal is to enact tax overhaul into law by the end of this year, not simply push it through the heavily Republican House, “so that we start 2018 in a new tax system.”

Rewriting the federal tax code, including lowering rates for corporate and personal income taxes, is a chief goal of President Donald Trump and congressional Republicans. So far it has been a struggle, with differences emerging within the party over how low they can push tax rates and which deductions might have to be eased or eliminated.

The “Better Way” campaign manifesto Ryan released last year stated that the GOP “envisions tax reform that is revenue neutral.” Even so, the question of whether tax cuts should be balanced with other budget savings to avoid worsening deficits has often caused tensions within the GOP.

The stakes in the tax battle have grown for the Republicans since their effort to repeal much of President Barack Obama’s law crashed this summer. That’s left them with no major legislative achievements during Trump’s initial year in office, despite GOP control of the White House and Congress.

Despite talks with Democrats on tax legislation, opposition by virtually all of them seems likely, meaning GOP lawmakers will have to be united.

On another major topic, Ryan said that immigration legislation Congress will be working on “will have to include security measures.”

During his presidential campaign and since, Trump has repeatedly promised to build a wall along the U.S.-Mexico border. Ryan said a physical wall doesn’t need to be constructed along the entire boundary, citing “circumstances on the ground that dictate how we do border security.”

Ryan said Trump took the right approach to phasing out a program that helped young immigrants brought to the country as children and now here illegally.

He said he wanted the White House to allow Congress time to address the issue because he didn’t want it “to be rescinded on day one and create chaos.” He said the six months that Trump has given lawmakers for action is enough time as the program winds down.

Trump has announced he will dismantle the Deferred Action for Childhood Arrivals program in six months. DACA has extended temporary work permits and deportation protection to nearly 800,000 younger immigrants brought to the U.S. as minors.

Ryan said that removing the immigrants covered by the program is “not in our nation’s interest.”

After months of disarray and confusion at the White House, Ryan said its operations have been getting better lately. He said the White House is “learning what works and I think they are improving.”

He would not say if improvements are due to changes such as John Kelly’s recent appointment as chief of staff or the departure of divisive former chief strategist Steve Bannon.

Kelly has been credited with instilling more order in the West Wing. He replaced the previous chief of staff, Reince Priebus, a Ryan friend.