During the 2016 election campaign, President Donald Trump called for the construction of a wall along the 1,954 mile border with Mexico for the purpose of minimizing “the illegal flow of drugs, cash, guns, and people across our border.”

During his first week in office, one of President Trump’s first executive actions was to order the Department of Homeland Security to start immediate construction of a U.S.-Mexico border wall. Weeks later, we now have some idea of how much that government infrastructure project will cost. USA Today reports:

PHOENIX — Building a wall or other barrier along the entire U.S.-Mexico border would cost about $21.6 billion and take up to 3½ years to complete, according to an internal Department of Homeland Secretary document.

The estimate is almost double the cost cited by President Trump — who made a border wall built at Mexico’s expense his signature issue throughout the presidential race — as well as new DHS Secretary John Kelly, who commissioned the report.

The document containing the estimate, first reported by Reuters, lays out a three-phase plan about where construction could begin along the 1,250 miles of border without physical barriers and it details challenges to constructing a wall.

It’s not surprising that the estimated cost of the proposed border wall has more than doubled over what candidate Trump suggested. That’s par for the course for any politician’s promises for spending, although it will be interesting to see if he can successfully negotiate the cost down. What is surprising is that even at that cost, it’s comparatively inexpensive and would be built much more quickly than several of the federal government’s other recent and ongoing infrastructure boondoggles.

That’s no joke! The classic modern example of billions of federal dollars being needlessly flushed away with little, if anything, to show for it is California’s bullet-train project, whose cost to U.S. taxpayers for its first 119 miles of track now exceeds $64 billion. John Merline of Investor’s Business Daily describes how ludicrous that federal project has become:

In the late 1800s, it took railroad companies six years to lay 1,907 miles of track for what was to become the Transcontinental Railroad (or as Barack Obama calls it, the Intercontinental Railroad).

Building that railroad line required tunneling through mountains — at one foot a day — building bridges — including one that spanned 700 feet — and doing all the work almost entirely by hand.

As best, it will now take seven years for California to lay 119 miles of track — on relatively flat ground in the middle of nowhere.

That news came from a contract revision that the Obama administration approved late last week. Instead of finishing the first leg of what is supposed to be a High-Speed Rail service from San Francisco to San Diego by 2018, the new deadline is 2022, which will be seven years after the January 2015 groundbreaking.

Even when completed, the first leg will only run from Madera (population 63,105) down to Shafter, a small town north of Bakersfield. Not exactly a heavy transportation corridor.

How much would you bet that, in four years, we’ll have more miles of new border wall built than bullet-train tracks laid in California, despite the latter having had a multi-year head start and billions more in funds?

Ideally, the U.S. government would not be spending money on either initiative, since both have multi-billion dollar price tags while also having questionable benefits. Even in an imperfect world, where we might choose which boondoggle to build, there’s no question as to which infrastructure project’s spigot of federal funds should be shut off first — the much more costly one.

If only the U.S. Congress would make those choices.