AUSTIN — A convention to change the founding document upon which America's democracy was established is a dangerous idea that could have frightening unintended consequences, concerned Texans told lawmakers Thursday.

"This convention, if it is ever called, is going to be a flaming zoo," Michael Openshaw, a Republican political activist, told the House Select Committee on State and Federal Power and Responsibility.

The committee considered a package of bills that would put Texas among a small but growing group of states calling for a convention of states to amend the U.S. Constitution. Gov. Greg Abbott and other lawmakers have received considerable funds from mega-rich donors behind a national movement for the convention. Abbott has been promoting the idea since last year, and he made the Convention of States an emergency item for the legislative session.

The states, Abbott and convention supporters maintain, must rein in a federal government that has run amok. The idea has generated controversy among political activists, and more than 150 signed up to testify for and against the convention plan Thursday.

Critics of the effort worry that such a convention could easily overreach the limited rewrites that supporters want and create a whole new constitution without public input or oversight.

"This convention will not go the way anybody who is advocating it would think," Openshaw said.

A convention is one of two ways the U.S. Constitution can be amended, and it's described in Article V. One way is that Congress can propose amendments approved by two-thirds of the members of both chambers. The other method allows two-thirds of the state legislatures to call for a convention to propose amendments. Republicans who back the idea are confident that because they control state government in a majority of states, their ideas would prevail.

In both cases, the amendments would become effective only if ratified by 38 states.

So far, the U.S. Constitution has been amended 27 times. None of those were amendments generated by a convention of states. Efforts to change the Constitution through a convention, initiated by both conservative and liberal advocates, have failed since the 1970s.

The House committee on Thursday considered several bills related to the convention. One outlines how delegates to such a convention would be chosen and the rules they would operate under. Another measure would repeal all but one of the 14 existing resolutions Texas lawmakers have approved since the 1899 that also called for a convention of the states.

A third measure would allow Texas to become one of 34 states needed to force Congress to initiate a convention of states to modify the U.S. Constitution.

The Senate easily approved the package of bills in February, and the House passed similar legislation last year.

Supporters say the convention of states is the best way to rein in both Congress and the U.S. Supreme Court, which have run roughshod over the states. A bill by Rep. Rick Miller, R-Sugar Land, seeks a convention that would impose fiscal restraints on the federal government, limit its power and jurisdiction, and create term limits for federal officials and members of Congress.

"I think we all agree that we have a problem with Washington," Miller said. "Courage is the price of liberty."

But opponents worry a convention will create opportunities for a select group of people to erode rights that the original Constitution created. They also are concerned that Congress would control the process and limit the effectiveness of the process.

"This is a terrible idea, and there is nothing wrong with our Constitution," Pat Carlson, former president of the conservative Texas Eagle Forum, told the committee.

The Convention of States Project is leading the charge for a convention in Texas and nationwide. It is a nonprofit that launched in 2013 to gin up national support for a convention to limit federal powers.

Midland oilman Tim Dunn is major conservative financier of the convention effort. Dunn has long been in a political battle with Republican House Speaker Joe Straus, whom he considers too moderate. Dunn and Empower Texans, a far-right conservative advocacy group funded largely by Dunn, have put millions of dollars into campaign efforts to unseat Straus and his allies.

Mark Meckler, executive director of the Convention of States Project, has said he is confident that with 2.1 million supporters nationally, momentum is building toward a successful effort to call a convention that supporters say will bring government closer to the people.