By David Morgan and Richard Cowan WASHINGTON (Reuters) – Democrats on Wednesday argued Donald Trump planted the seeds for the deadly attack on the U.S. Capitol long before Jan. 6 with false claims the 2020 election was stolen, and said lawmakers had an obligation to hold the former president accountable. The House of Representatives has charged Trump, a Republican, with inciting an insurrection by exhorting thousands of supporters to march on the Capitol on the day Congress was gathered to certify Democrat Joe Biden’s electoral victory. The rioters stormed the building, sending lawmakers into …