Speaker Pelosi urged the House Democrats to sign a resolution to challenge President Trump's declaration of a national emergency to build the border wall.

This is the proper procedure to test a president's declaration of national emergency.

If Congress disagrees with the declaration of an emergency, it can pass a joint resolution to oppose it.  But the president can veto that resolution, and then Congress would have to override the veto.  The law provides the mechanism for Congress to challenge the declaration of an emergency.  This means that the plain language of the law leaves it to the president and Congress, the elected political branches of government, to determine a national emergency.  It means that it is not an issue for the federal courts, because the statute has a clearly written procedure for the elected branches of government to resolve any dispute about whether the president is properly following the National Emergencies Act.

The Democrats don't have the votes to override a veto.

California, joined by 15 other states, has filed suit in federal court in the Northern District of California, in the Ninth Circuit.

California contends that President Trump cannot re-allocate funds for the wall and that there is no emergency because illegal entries are at a 45-year low.

The factual basis for the declaration of a national emergency to build the wall is the number of illegals, the cost of illegals in terms of welfare and other governmental payments, the crimes committed by illegals as a percentage of the illegals in our country, the drugs smuggled across the border, and the ease with which terrorists can cross the border.  These are some of the factual issues for Congress and the president to resolve, not a judge.

The courts should not hear the case because of the constitutional doctrine of "political question."  Generally, this means that an issue is so political that federal courts should not hear the issue and should leave it to the Executive and Legislative Branches to resolve.  This doctrine also involves the separation of powers, where each branch has its constitutionally prescribed role.  The doctrine is also referred to as the justiciability doctrine.

We elected Congress and the president to resolve the issue of border security.  We didn't elect federal judges to hold hearings on whether we need a wall.  This is the responsibility of Congress and the president.

If the Democrats in the House and Senate have evidence that a border wall is not necessary, then let them present such evidence in Congress and debate it, and then vote so the American voters know the position of each member.

The Dems will lose on the resolution because they don't have the votes to override a veto.

California, a proxy for the Democrats, will lose the lawsuit because the case is not justiciable.  If the district court rules for California, there will be expedited appeals to the Ninth Circuit and the Supreme Court, if necessary, which will rule correctly.