GBP/USD was near session highs, extending the previous session's rebound from 2-month lows50EMA, the 13-day downtrend line challenges the bulls of the pairThe RSI decline supports the pair's rebound correction from 100EMA, and the uptrend line since the end of November has also challenged the sterling bearsWith British and U.S. markets closed for the Memorial Day holiday, the pound pared its monthly decline against the dollar near 1.2360 in European trade on Monday morning. The pair extended the previous day's rally from levels seen since early April, as the dollar retreated from multi-day highs despite the Biden-mccarthy deal to extend the debt ceilingThe RSI line is below 50 and currently stands at 14, plus the 100EMA moving average is providing support for the pound near the round 1.2300 level.Even so, the bearish MACD signal and the confluence of resistance at 1.2400 (including 50EMA and the downtrend line two weeks ago) limit the short-term upside of GBP/USD.After that, the late 2022 top and last month's top near 1.2440 and 1.2585, respectively, could act as the last line of defense for sterling bears.Conversely, a break below the 100EMA moving average of 1.2300 would not invite the GBP bears to enter, as the uptrend support line since November 2022 near 1.2230 could limit further declines in the pair.However, a clear break below the support level of 1.2230 would quickly challenge the round number of 1.2000 and then the low of early 2023 around 1.1840.