A political climate that's already more overheated than any time in a generation. Plans for a large-scale rally of firearms enthusiasts in the nation's capital. A fast-growing group of (mostly ex-) military and cops that pledges to disobey "unconstitutional orders" from the president, and an "urgent" call from the group's leader to flood Washington to "shout your oaths in the tyrant's face" -- on the 15th anniversary of the worst home-grown terror incident in U.S. history, the Oklahoma City bombing.

What could possibly go wrong?

The world will find out on April 19, now that the leader of the Oath Keepers -- the alliance of mostly veterans and ex-cops that didn't exist at the start of the Obama administration but now claims nearly 15,000 members -- has issued that urgent call to all members to attend two politically charged events in or around Washington on that Monday, which organizers stress as the 235th anniversary of the first shots of the American Revolution.

Stewart Rhodes, the Yale law school grad and ex-paratrooper who founded the Oath Keepers after working on Rep. Ron Paul's 2008 presidential campaign, sent out an email blast to members over the weekend urging them to attend either a Second Amendment March on the Capitol that's slated to take place on Washington that day, or an open-carry rally in which many attendees will be bringing their firearms, to be held just across the Potomic River at Fort Hunt National Park.

(In an irony that event organizers don't seem to be playing up, open-carry of weapons used to be banned at national parks before February of this year, when a longstanding ban was overturned in legislation signed by the man Rhodes alluded to as "a tyrant," President Barack Obama.)

The Second Amendment March has been in the planning stages for months but only started gaining attention recently, in the hypercharged environment after the enactment of health care legislation vehemently opposed by members of right-wing groups like the Oath Keepers.

In particular, news accounts noted that a long-time militia activist -- Mike Vanderboegh of Alabama -- has said that he plans to speak at the Fort Hunt rally. It was Vanderboegh -- who recently founded a group similar to the Oath Keepers called The Three Percenters -- who made headlines last week by issuing an appeal on his blog for supporters to break the windows of healthcare reform supporters; immediately after that, windows and doors were smashed at Democratic offices in Wichita, Kansas, and Rochester, N.Y. and the offices of an Arizona congresswoman, among others.

In promoting the events, the Oath Keepers' Rhodes -- who says he will be speaking at both rallies -- states:

You took an oath to support and defend the Constitution of the United States against all enemies, foreign and domestic. The time has come to keep that oath by taking a firm stand, to let the oath breakers in DC know that you and yours will not submit and go quietly as they "transform" our Constitutional Republic into what will rightly meet the definition of a totalitarian state (without limits on its powers, which it creates for itself out of thin air without the consent of the people).

Can the Oath Keepers deliver a big crowd to the events? The group has clearly experienced a surge of members since it was launched on the same date, April 19, last year at a rally on Lexington Green in Massachusetts where Vanderboegh -- according to an excellent profile of the Oath Keepers by Justine Sharrock for Mother Jones -- was also present. It's not known if the group's claim of more than 14,000 members is accurate. The Oath Keepers do have about 17,750 followers on Facebook and more than 1,500 followers on Twitter.

The rise of the Oath Keepers has already aroused alarm from hate groups trackers like the Southern Poverty Law Center (PDF file) and the Anti-Defamation League as at the vanguard of a new breed of "Patriot" groups touting conspiracy theories about the government that have increased in intensity since Obama took office. The core issue for the Oath Keepers is a list of orders that its members will not obey -- these include rounding up Americans and placing them in concentration camps or confiscating guns from U.S. citizens.

Several of the speakers at the April 19 Second Amendment March also have been monitored over the years by SPLC, ADL and others for connections to militias and other far-right movements. These include Larry Pratt of the Gun Owners of America --a group that's been famously described as "the NRA on steroids" and former Arizona sheriff Richard Mack, who is a member of the Oath Keepers as well.

In his plea for attendees, Rhodes describes health care reform and the takeover of General Motors as examples of the government's descent into tyranny, but he also urged supporters to obey the District of Columbia's strict gun laws, adding "you will also be showing your support for fellow Americans who are merely exercising their right to free speech, to peaceably assemble, to association, to petition their government for a redress of grievances, and their right to keep and bear arms."

Answering his own question as to why the Fort Hood event is "open carry," Rhodes responds, "Why not?" He notes that other open-carry rallies, including one at the Kentucky state capitol, have been held with incident.