Speaker of the House Rep. Paul Ryan says shutting down the government over funding for the border wall is "not necessary" and urged the president not to veto a debt ceiling bill to avoid a government shutdown.

Ryan's statement sets up a showdown between Trump and the GOP Congress over funding for the wall, which Ryan says will be dealt with in the appropriations process but the president wants included in the debt ceiling bill.

CNN:

"I don't think a government shutdown is necessary and I don't think most people want to see a government shutdown, ourselves included," the leader of the Republican-controlled House said at a news conference in Oregon where he was promoting tax reform.

Ryan argued the House had already passed funding for border security but that the narrowly divided Senate – where Democrats have considerably more sway over what gets into funding bills – would need more time to act.

"The fact is though, given the time of year it is and the rest of the appropriations we have to do, we are going to need more time to complete appropriations process particularly in the Senate," Ryan said.

Ryan also said a short-term government funding bill, known as a continuing resolution, would probably be needed to keep the government open past September.

At a raucous rally in Phoenix Tuesday night, Trump said he would insist on the border wall funding.

"If we have to close down our government, we're building that wall," Trump said.

Senate Minority Leader Chuck Schumer also warned against a shutdown over the border security issue.

“If the President pursues this path, against the wishes of both Republicans and Democrats, as well as the majority of the American people, he will be heading towards a government shutdown which nobody will like and which won't accomplish anything," the New York Democrat said in a statement.

In the current politically polarized environment – when Trump is battling Republicans on the Hill as hard as he is Democrats – it's highly uncertain if a government shutdown can be avoided. But GOP leaders on the Hill have made clear their desire to avoid the potentially politically damaging outcome.

Trump is trying to put pressure on GOP senators to approve border wall funding already OKed by the House.  There are about a dozen Republican senators who have serious reservations about the wall but, with the proper motivation from Trump, will probably vote to approve it.

Is holding a gun to their head, threatening a government shutdown, the way to go about funding the wall?  The problem for Trump is that what he is asking for is outside of the appropriations process – a process that, while rarely followed, is nevertheless the law of the land.  The problem for the GOP senators is that if there is a government shutdown, they will be blamed.  There is room for compromise there if both sides give a little.

Ryan's problem is that he needs a few Democrats to get the debt ceiling bill passed in the House.  And Democrats have sworn they will not vote for the increase if the debt ceiling bill contains funding for the wall. 

So the battle lines have been drawn.  It will take some statesmanship from all sides to avoid the drama of a shutdown – something no one in Washington has demonstrated in a long while.